. . "British Broadcasting Corporation." . . . . . . . . "A change of key" . . . . "This program explains how different musical scales require different sharps and flats to work, and how the normal keyboard is designed to accommodate this, starting with the major scale beginning on C. The color and variey of expression that modulation or change of key introduces to musical composition is demonstrated." . "Composition (Music)" . . "Music Instruction and study." . . "Open University." . . "Musical intervals and scales." . .