A d a m   K a d m o n :
The Guitar Grimoire: A Compendium of Formulas for Guitar Scales and Modes ©1995 Carl Fischer

J o d y   F i s h e r :
Guitar Mode Encyclopedia: 21 Modes of the Major, Melodic Minor & Harmonic Minor Scales ©1994 Alfred Publishing

M i k e   C h r i s t i a n s e n :
Mel Bay's Complete Guitar Scale Dictionary ©1992 Mel Bay Publications

N i c o l a s   S l o n i m s k y :
Thesaurus of Scales and Melodic Patterns ©1975 Charles Scribners' Sons

F r a n c o   D ' A n d r e a   &   A t t i l i o   Z a n c h i :
Enciclopedia Comparata delle Scale e Degli Accordi ©1991 Nuova Carisch

R o n   M i d d l e b r o o k :
Scales and Modes in the Beginning: Created Especially for Guitarists ©1982 Centerstream Publications

F r a n k   G a m b a l e :
Technique Book: The Essential Soloing Theory Course for All Guitarists Book I ©1989 Mark Varney

A l   P o l i t a n o :
Chords, Scales, Arpeggios for the Guitarist ©1983 Centerstream Publications

The New Grove Dictionary of Music & Musicians,
The New Harvard Dictionary of Music, The Oxford Dictionary of Music
...plus websites and magazine articles WAAAAY too numerous to mention.