Date of Award
Following the probable order of their appearance in history, all instruments may be placed under three general heads: Percussion instruments, wind instruments, and stringed instruments.
The percussion instruments are further divided into two distinct groups: Instruments with indefinite pitch and instruments with definite pitch.
The mallet instruments are actually a group of definite pitch instruments with vibrating wood or metal plates. They are further divided according to tonal features.
Kirkpatrick, Lois, "Mallet Instruments" (1970). Honors Theses. 497.