Kite Guitar: Difference between revisions
→Fretboard charts (downmajor tuning): changed "off zone" to "complex zone" |
added the Kite Fretboard Visualizer Tool, added the Russian tuning, added the d-fret, changed Jason to Deja, other small changes too |
||
Line 4: | Line 4: | ||
This is a brief explanation, see also the longer one at [[Kite Guitar explanation for non-microtonalists]]. | This is a brief explanation, see also the longer one at [[Kite Guitar explanation for non-microtonalists]]. | ||
The Kite guitar (or bass, mandolin, banjo, etc.) combines the beauty of just intonation with the freedom of an equal temperament. Kite guitar is short for Kite-''fretted'' guitar. It has 41 notes per the octave instead of 12. [[41edo|41-tET aka 41-equal aka 41edo]] approximates 7-limit just intonation to within 3-6 [[cents]], and chords sound gorgeous! But a guitar with 41 frets per octave is physically challenging to play. Kite-fretting cleverly omits every other fret. Thus while the frets are closer together than a standard guitar, the Kite guitar is still quite playable. There are 20'''½''' frets per octave, thus it's about as playable as [[19edo|19-equal]] or [[22edo|22-equal]]. The interval between open strings is 13 steps of 41. Because 13 is an odd number, <u>all 41 pitches are present on the guitar</u>. Each string has only half of the pitches, but any adjacent pair of strings has all 41. | The Kite guitar (or bass, mandolin, banjo, etc.) combines the beauty of just intonation with the freedom of an equal temperament. Kite guitar is short for Kite-''fretted'' guitar. It has 41 notes per the octave instead of 12. [[41edo|41-tET aka 41-equal aka 41edo]] approximates 7-limit just intonation to within 3-6 [[cents]], and chords sound gorgeous! But a guitar with 41 frets per octave is physically challenging to play. Kite-fretting cleverly omits every other fret. Thus while the frets are closer together than a standard guitar, the Kite guitar is still quite playable. There are 20'''½''' frets per octave, thus it's about as playable as [[19edo|19-equal]] or [[22edo|22-equal]]. The interval between open strings is usually 13 steps of 41. Because 13 is an odd number, <u>all 41 pitches are present on the guitar</u>. Each string has only half of the pitches, but any adjacent pair of strings has all 41. | ||
Omitting half the frets (known as [[skip-fretting]]) in effect moves certain pitches to remote areas of the fretboard, and makes certain intervals difficult to play. Magically, it works out that the remote intervals are the ones that don't work well in chords, and the ones that aren't remote are the ones that do work well. For example, the sweet 5-limit major 3rd, a [[5/4]] ratio, is easily accessible, but the dissonant 3-limit major 3rd [[81/64]] isn't. (3-limit & 5-limit refer to the largest prime number in the frequency ratio.) | Omitting half the frets (known as [[skip-fretting]]) in effect moves certain pitches to remote areas of the fretboard, and makes certain intervals difficult to play. Magically, it works out that the remote intervals are the ones that don't work well in chords, and the ones that aren't remote are the ones that do work well. For example, the sweet 5-limit major 3rd, a [[5/4]] ratio, is easily accessible, but the dissonant 3-limit major 3rd [[81/64]] isn't. ([[Harmonic limit|3-limit & 5-limit]] refer to the largest prime number in the frequency ratio.) | ||
In addition, important 7-limit intervals like [[7/6]], [[7/5]] and [[7/4]] are easy to play. This means the Kite guitar can do much more than just play sweet Renaissance music. It can put a whole new spin on jazz, blues and experimental music. The dom7 and dom9 chords are especially calm and relaxed, revealing just how poorly 12- | In addition, important 7-limit intervals like [[7/6]], [[7/5]] and [[7/4]] are easy to play. This means the Kite guitar can do much more than just play sweet Renaissance music. It can put a whole new spin on jazz, blues and experimental music. The dom7 and dom9 chords are especially calm and relaxed, revealing just how poorly 12-equal tunes these chords. But dissonance is still possible, in fact 41-equal can be far more dissonant than 12-equal. And 41 notes means that the melodic and harmonic vocabulary is greatly expanded, allowing truly unique music that simply isn't possible with 12 notes. | ||
The interval between open strings is usually a major 3rd, not a 4th. Thus new chord shapes must be learned. However, the Kite guitar is isomorphic, meaning that chord shapes can be moved not only from fret to fret but also from string to string. Thus there are far fewer shapes to learn. (Open tunings, which are non-isomorphic, are also possible.) Tuning in 3rds not 4ths reduces the overall range of the guitar. Thus a 7-string or even an 8-string guitar is desirable. | The interval between open strings is usually a major 3rd, not a 4th. Thus new chord shapes must be learned. However, the Kite guitar is isomorphic, meaning that chord shapes can be moved not only from fret to fret but also from string to string. Thus there are far fewer shapes to learn. (Open tunings, which are non-isomorphic, are also possible.) Tuning in 3rds not 4ths reduces the overall range of the guitar. Thus a 7-string or even an 8-string guitar is desirable. | ||
Line 15: | Line 15: | ||
== About 41-equal == | == About 41-equal == | ||
[[41-edo|41-equal (aka 41edo)]] has steps of 29.27¢. It approximates 7-limit [[just intonation]] very closely. Prime 3 is extremely accurate, and primes 5 and 7 are both tuned flat, which means their errors partially cancel out in ratios such as 7/5. Prime 11 is also quite accurate. But unfortunately it's tuned sharp, so the errors can add up, and 11/10 is nearly 11¢ sharp. Primes 13 and 17 are further off, and accurate intonation requires microbending. | [[41-edo|41-equal (aka 41edo)]] has steps of 29.27¢. It approximates 7-limit [[just intonation]] very closely. Prime 3 is extremely accurate, and primes 5 and 7 are both tuned slightly flat, which means their errors partially cancel out in ratios such as 7/5. Prime 11 is also quite accurate. But unfortunately it's tuned sharp, so the errors can add up, and 11/10 is nearly 11¢ sharp. Primes 13 and 17 are further off, and accurate intonation requires microbending. | ||
{| class="wikitable center-all" | {| class="wikitable center-all" | ||
! prime | ! prime | ||
Line 411: | Line 411: | ||
==Tunings== | ==Tunings== | ||
Unfortunately, tuning the Kite guitar to EADGBE causes the conventional chord shapes to have | Unfortunately, tuning the Kite guitar to EADGBE causes the conventional chord shapes to have wolfy offperfect intervals that are only 1 edostep away from perfect. For example, the usual E major chord shape 0 2 2 1 0 0 would translate to either 0 3 3 2 0 0 = E vB vE G# B E, or else 0 4 4 2 0 0 = E ^B ^E G# B E. Either way, the chord contains three offperfect octaves and two offperfect fifths. (In addition, the major 3rd isn't 5/4 but 81/64.) The usual Em, A, Am, D, Dm, G and C chord shapes also have offperfect intervals. The tuning can be slightly adjusted so that one of these chord shapes is in tune. For example, E ^A ^D ^G B E puts E downmajor = 0 3 3 1 0 0 in tune, as well as E upminor = 0 3 3 0 0 0. While this is an improvement, the other chord shapes still have offperfect intervals. No adjustment to EADGBE will get more than a few of the conventional chord shapes in tune. Thus learning new chord shapes is inevitable. | ||
There are two main types of tunings. '''Isomorphic tunings''' in 3rds facilitate playing 7-limit chords and chord progressions, and exploring the 7-limit lattice. '''Open tunings''' such as DADGAD facilitate exploring the 13-limit tonality diamond. | There are two main types of tunings. '''Isomorphic tunings''' in 3rds facilitate playing 7-limit chords and chord progressions, and exploring the 7-limit lattice. '''Open tunings''' such as DADGAD facilitate exploring the 13-limit tonality diamond. | ||
There are two types of Kite guitar fretboards, even-frets and odd-frets. In the former, all or almost all of the frets are an even number of edosteps from the nut. In the latter, it's an odd number. In general, the even-fret layout is for isomorphic tunings and the odd-frets layout is for open tunings. | There are two types of Kite guitar fretboards, even-frets and odd-frets. In the former, all or almost all of the frets are an even number of edosteps from the nut. In the latter, it's an odd number. In general, the even-fret layout is for isomorphic (or dimorphic, see below) tunings and the odd-frets layout is for open tunings. | ||
Isomorphic means "same shape", and there is only one shape to learn for any chord. The standard isomorphic tuning is the '''downmajor tuning''', in which adjacent open strings are tuned a downmajor 3rd apart. Alternative isomorphic tunings use an upminor 3rd or an upmajor 3rd. | Isomorphic means "same shape", and there is only one shape to learn for any chord. The standard isomorphic tuning is the '''downmajor tuning''', in which adjacent open strings are tuned a downmajor 3rd apart. Alternative isomorphic tunings use an upminor 3rd or an upmajor 3rd. Two possible '''dimorphic''' ("two shapes") tunings are the '''alternating thirds''' tuning (alternates downmajor 3rds with upminor 3rds), and the '''plain tuning''' (alternates plain perfect 4ths with plain major 2nds). The drawback to dimorphism is that every chord has two shapes. The advantage is that the open strings make a diatonic scale. The '''trimorphic''' ("three shapes") '''Russian tuning''' is based on the traditional Russian tuning DGBDGBD, but with vB not B. | ||
*[http://tallkite.com/misc_files/The%20Kite%20Tuning%20downmajor%20fretboard.pdf '''Fretboard chart for the downmajor tuning'''] | *[http://tallkite.com/misc_files/The%20Kite%20Tuning%20downmajor%20fretboard.pdf '''Fretboard chart for the downmajor tuning'''] | ||
*[http://tallkite.com/misc_files/The%20Kite%20Tuning%20upminor%20fretboard.pdf '''Fretboard chart for the upminor tuning'''] | *[http://tallkite.com/misc_files/The%20Kite%20Tuning%20upminor%20fretboard.pdf '''Fretboard chart for the upminor tuning'''] | ||
Line 423: | Line 423: | ||
DADGAD lacks both the 4th and the rainbow of four 6ths in the lower octave. A seven-string DGADGAD tuning remedies this. | DADGAD lacks both the 4th and the rainbow of four 6ths in the lower octave. A seven-string DGADGAD tuning remedies this. | ||
Open tunings become more playable with the use of a "half-fret capo". From | Open tunings become more playable with the use of a "half-fret capo". From [[Deja Igliashon]]'s liner notes (see the [[41edo#Kite Guitar Recordings|Recordings]] section): | ||
"A couple of improvisations on a guitar loaned to me by Kite Giedratis. The guitar is fretted to 41 notes per double-octave, i.e. every other note of 41 notes per octave, using movable cable ties. On these tracks I modified the fretting slightly by moving the 2nd fret down one step of 41edo and then put a capo behind it, effectively moving all the frets above it UP by one step of 41edo, so that the frets all give odd-numbered pitches from 41edo instead of even-numbered ones. This gives frets for approximations to the ratios 21/20, 12/11, 9/8, 7/6, 6/5, 5/4, 9/7, 4/3, 11/8, and 10/7 relative to the open strings, which makes it possible to let the open strings ring out against pitches fretted low on the neck when the open strings are tuned to DADGAD or DGDGAD, my two favorite open tunings. | "A couple of improvisations on a guitar loaned to me by Kite Giedratis. The guitar is fretted to 41 notes per double-octave, i.e. every other note of 41 notes per octave, using movable cable ties. On these tracks I modified the fretting slightly by moving the 2nd fret down one step of 41edo and then put a capo behind it, effectively moving all the frets above it UP by one step of 41edo, so that the frets all give odd-numbered pitches from 41edo instead of even-numbered ones. This gives frets for approximations to the ratios 21/20, 12/11, 9/8, 7/6, 6/5, 5/4, 9/7, 4/3, 11/8, and 10/7 relative to the open strings, which makes it possible to let the open strings ring out against pitches fretted low on the neck when the open strings are tuned to DADGAD or DGDGAD, my two favorite open tunings. | ||
Line 430: | Line 430: | ||
But anyway, the two designs can coexist on the same fretboard by simply inserting an extra fret between the 1st and 2nd instead of moving the 2nd fret lower as I have done, and by varying the tuning of the open strings as you please. It's a fantastic way to access the resources of 41edo on a guitar, without having an absurd number of very closely-spaced frets!" | But anyway, the two designs can coexist on the same fretboard by simply inserting an extra fret between the 1st and 2nd instead of moving the 2nd fret lower as I have done, and by varying the tuning of the open strings as you please. It's a fantastic way to access the resources of 41edo on a guitar, without having an absurd number of very closely-spaced frets!" | ||
Deja has since explored other open tunings besides DADGAD and DGDGAD, such as E A vC# vG B ^^D (a 3:4:5:7:9:11 chord) and D A D vF# vC E (a 2:3:4:5:7:9 chord). They prefer placing the first fret 3 edosteps above the nut. This creates a half-fret offset without a capo. A capo on the 1st fret could remove the half-fret offset, if desired. | |||
How to implement the half-fret capo trick: An extra fret slot is cut to allow insertion of a temporary fret in between the nut and the 1st (permanent) fret, or if the action is too high to capo there, then between the 1st and 2nd (permanent) frets. The slot stops short of the treble side of the fretboard. So gravity holds it in place, plus of course the capo. The temporary fret has the barbs on the side of the tang filed off. The extra slot is a bit wider, so the fret can be pulled out easily. It goes in from the side, under the strings, so the strings don't need to be loosened. It can be inserted and removed on stage between songs. The fret is a bit longer, sticks out about 1 inch, so that you can pull it out easily. Putting a large piece of wide tape on the part that sticks out helps prevent it from being lost. | How to implement the half-fret capo trick: An extra fret slot is cut to allow insertion of a temporary fret in between the nut and the 1st (permanent) fret, or if the action is too high to capo there, then between the 1st and 2nd (permanent) frets. The slot stops short of the treble side of the fretboard. So gravity holds it in place, plus of course the capo. The temporary fret has the barbs on the side of the tang filed off. The extra slot is a bit wider, so the fret can be pulled out easily. It goes in from the side, under the strings, so the strings don't need to be loosened. It can be inserted and removed on stage between songs. The fret is a bit longer, sticks out about 1 inch, so that you can pull it out easily. Putting a large piece of wide tape on the part that sticks out helps prevent it from being lost. | ||
Line 435: | Line 437: | ||
Alternatively, the extra fret can be a permanent one. The extra fret is indicated in tablature by a letter: "a" if it's between the nut and the 1st fret, "b" if it's between the 1st and 2nd frets, etc. | Alternatively, the extra fret can be a permanent one. The extra fret is indicated in tablature by a letter: "a" if it's between the nut and the 1st fret, "b" if it's between the 1st and 2nd frets, etc. | ||
A d-fret makes a 9/8 interval with the nut. Combined with the alternating 3rds tuning, it makes playing 5-limit music in first position possible. A b-fret and/or an e-fret can also be useful. | |||
==Fretboard charts (downmajor tuning)== | ==Fretboard charts (downmajor tuning)== | ||
This chart is in relative not absolute notation, meaning it shows intervals not notes. At the bottom is P1, a perfect unison. This is the tonic of the scale, or the root of the chord. This chart shows all the intervals within easy reach of this note, up to an octave. There are four "rainbows": one of 2nds, one of 3rds, one of 6ths, and one of 7ths. These plus the 4th, 5th, | |||
=== Relative charts (Intervals) === | |||
This chart is in relative not absolute notation, meaning it shows intervals not notes. At the bottom is P1, a perfect unison. This is the tonic of the scale, or the root of the chord. This chart shows all the intervals within easy reach of this note, up to an octave. There are four "rainbows": one of 2nds, one of 3rds, one of 6ths, and one of 7ths. These plus the 4th, 5th, various tritones and 2 other notes add up to 25 of the 41 notes. Every single ratio of [[odd-limit]] 9 or less appears here. | |||
[[File:The Kite Tuning.png|none|thumb|416x416px]] | [[File:The Kite Tuning.png|none|thumb|416x416px]] | ||
This chart boils the information down to the essentials: interval name and (via color) general type of ratio. | This chart boils the information down to the essentials: interval name and (via color) general type of ratio. | ||
Line 447: | Line 451: | ||
[[File:The Kite Tuning 2.png|none|thumb|900x900px]] | [[File:The Kite Tuning 2.png|none|thumb|900x900px]] | ||
This chart extends even further, showing the "rainbow zones" and the "complex zones". When two guitarists play together, it's very natural for one to play chords in the lower rainbow zone, and another to solo in the higher rainbow zone. The open strings tend to be in a complex zone, unless the tonic is fairly close to the nut, or else up around the 3rd or 4th dot. [[File:The Kite Tuning 3.png|none|thumb|900x900px]] | This chart extends even further, showing the "rainbow zones" and the "complex zones". When two guitarists play together, it's very natural for one to play chords in the lower rainbow zone, and another to solo in the higher rainbow zone. The open strings tend to be in a complex zone, unless the tonic is fairly close to the nut, or else up around the 3rd or 4th dot. [[File:The Kite Tuning 3.png|none|thumb|900x900px]] | ||
This chart shows the actual notes of an 8-string Kite guitar. The notes circled in red are the open strings of a 12-equal guitar. The ideal string gauges for this tuning are discussed in the [[Kite Guitar | |||
[[File:Fretboard 4.png|none|thumb|900x900px]] | === Absolute charts (notes) === | ||
The [https://docs.google.com/spreadsheets/d/15W4lBGB2ozkaAdsZypBbq9bI7IGSIwOtDpBD5SHxI6c/edit?gid=778743397#gid=778743397 Kite Fretboard Visualizer Tool] is a google spreadsheet that generates a fretboard showing all the notes of a chord or scale. Unhiding columns will reveal several extra frets. Here's the F downmajor scale: | |||
[[File:Kite Fretboard Visualizer Tool.png|none|thumb|472x472px]] | |||
This chart shows the actual notes of an 8-string Kite guitar. The notes circled in red are the open strings of a 12-equal guitar. The ideal string gauges for this tuning are discussed in the [[How to make a Kite Guitar]] page. Every 4th fret has a set of one, two or three dots. Three dot sets equals a 5th. The dots run single-double-triple-single-double-triple etc. One set of single-double-triple is called a "kite" (due to its shape). There is a low kite, a mid kite and sometimes a high kite. Each dot set can be named low single, mid double, etc. See [[KDF Fret Numbering]].[[File:Fretboard 4.png|none|thumb|900x900px]] | |||
A 6-string guitar is usually tuned to the middle 6 strings of the full 8 strings: | A 6-string guitar is usually tuned to the middle 6 strings of the full 8 strings: | ||
[[File:Fretboard 4-6.png|none|thumb|900x900px]] | [[File:Fretboard 4-6.png|none|thumb|900x900px]] | ||
Line 727: | Line 734: | ||
Comma pumps, other than the aforementioned minicommas, cause pitch shifts, or occasionally, a tonic drift. The shift/drift is generally by a half-fret (a single edostep). Shifts of a full fret don't feel like shifts but more like reharmonizing/remelodizing, and full-fret drifts feel more like modulating. | Comma pumps, other than the aforementioned minicommas, cause pitch shifts, or occasionally, a tonic drift. The shift/drift is generally by a half-fret (a single edostep). Shifts of a full fret don't feel like shifts but more like reharmonizing/remelodizing, and full-fret drifts feel more like modulating. | ||
The two most common commas that cause issues are the [[81/80|Gu]] and [[64/63|Ru]] commas. The choice of which two chords in the pump contain the pitch shift can be tricky. Generally, root movement by an offperfect interval is avoided. This usually necessitates a root movement by a plain major or minor interval. | The two most common commas that cause issues are the [[81/80|Gu]] and [[64/63|Ru]] commas. The choice of which two chords in the pump contain the pitch shift can be tricky. Generally, root movement by an offperfect interval is avoided. This usually necessitates a root movement by a plain major or plain minor interval. | ||
For example, I - VIm - IIm - V7 - I is a Gu pump. Without the pump, I - VIm would be translated as Iv - vVI^m, to avoid shifts. The roots would move by a vM6. With the pump, this might translate to Iv - VI^m - II^m - Vv7 - Iv. The first root movement is by a M6. The tonic and the major 3rd both shift between the I chord and the VI chord. | For example, I - VIm - IIm - V7 - I is a Gu pump. Without the pump, I - VIm would be translated as Iv - vVI^m, to avoid shifts. The roots would move by a vM6. With the pump, this might translate to Iv - VI^m - II^m - Vv7 - Iv. The first root movement is by a M6. The tonic and the major 3rd both shift between the I chord and the VI chord. | ||
Line 737: | Line 744: | ||
One way to hide pitch shifts is to voice the two occurrences of the pitch in different octaves. Failing that, at least put them in a middle voice, not the top or bottom voice, so as to be less prominent. Another way is to omit the 5th in one of the chords. Thus in the Gu example, the 2nd chord might be VI^mno5. Another trick is to delay the entrance of the 2nd note a beat or two, or end the 1st note a little early. In a polyphonic context, it helps if the shifting note is in two voices of different timbres. If you're recording, you can pan the 2 close notes to different sides. Remember, the ear <u>wants</u> to hear the two notes as the same, and only needs a little encouragement to do so. | One way to hide pitch shifts is to voice the two occurrences of the pitch in different octaves. Failing that, at least put them in a middle voice, not the top or bottom voice, so as to be less prominent. Another way is to omit the 5th in one of the chords. Thus in the Gu example, the 2nd chord might be VI^mno5. Another trick is to delay the entrance of the 2nd note a beat or two, or end the 1st note a little early. In a polyphonic context, it helps if the shifting note is in two voices of different timbres. If you're recording, you can pan the 2 close notes to different sides. Remember, the ear <u>wants</u> to hear the two notes as the same, and only needs a little encouragement to do so. | ||
In much music, especially pre-20th-century music, the dissonance of the dom7 chord is what drives the V7 - I cadence and gives the music momentum. But 41-equal's smooth v7 chord is like a guard dog that smiles and wags its tail at strangers instead of barking. It's <u>too</u> relaxed! And the 7-limit intervals can sound out of place in a pre-20th-century context. One might instead use Vv,7 (down add-7, with a plain minor 7th) or Vv | In much music, especially pre-20th-century music, the dissonance of the dom7 chord is what drives the V7 - I cadence and gives the music momentum. But 41-equal's smooth v7 chord is like a guard dog that smiles and wags its tail at strangers instead of barking. It's <u>too</u> relaxed! And the 7-limit intervals can sound out of place in a pre-20th-century context. One might instead use Vv,7 (down add-7, with a plain minor 7th) or Vv^7 (down up-7, with an upminor 7th). For example, Am - G - F - E7 can be translated as A^m - ^Gv - ^Fv - Ev^7. (This also avoids a pitch shift.) | ||
For 20th-century music, a Vv7 chord is often appropriate. But when a stronger cadence to the I chord is desired, a V^7 chord often works better. For example, IIm7 - V7 - IM7 could be translated as either II^m7 - Vv7 - IvM7 or IIvm7 - Vv7 - IvM7. But the v7 chord is actually smoother than the vM7 chord, so both progressions feel unfinished. Often II^m7 - V^7 - IvM7 is better. The II^m7 chord has two notes in common with V^7. It feels somewhat like a | For 20th-century music, a Vv7 chord is often appropriate. But when a stronger cadence to the I chord is desired, a V^7 chord often works better. For example, IIm7 - V7 - IM7 could be translated as either II^m7 - Vv7 - IvM7 or IIvm7 - Vv7 - IvM7. But the v7 chord is actually smoother than the vM7 chord, so both progressions feel unfinished. Often II^m7 - V^7 - IvM7 is better. The II^m7 chord has two notes in common with V^7. It feels somewhat like a V11noRno3 chord. If a 9th is added to the V^7 chord, there are three common notes, and the progression feels even more connected. | ||
In IIm - V7 - I, where the I chord has no 7th, Vv7 works well. The progression can be tuned either II^m7 - Vv7 - Iv or IIvm7 - Vv7 - Iv. The IIvm7 chord is more connected to the V chord than II^m7. The Vv7 chord also works if the I chord has a minor 7th, i.e. Iv7. | In IIm - V7 - I, where the I chord has no 7th, Vv7 works well. The progression can be tuned either II^m7 - Vv7 - Iv or IIvm7 - Vv7 - Iv. The IIvm7 chord is more connected to the V chord than II^m7. The Vv7 chord also works if the I chord has a minor 7th, i.e. Iv7. | ||
These are all just guidelines, not hard and fast rules! There is often more than one good way to translate a song. | |||
===Translating microtonal material=== | ===Translating microtonal material=== | ||
Line 753: | Line 760: | ||
''Main article:'' [[Kite Guitar originals|'''Kite Guitar originals''']] | ''Main article:'' [[Kite Guitar originals|'''Kite Guitar originals''']] | ||
Like translations, these are grouped by the creator. If you have originals, | Like translations, these are grouped by the creator. If you have originals, please create your own page and link to it! | ||
==Further materials== | ==Further materials== |