TY  - BOOK
AU  - Darby,Gene
TI  - What is a simple machine? 
T2  - The What is it series 
U1  - 531.8 DAR 
PY  - 1969///
CY  - Louisville, Ky.
PB  - American Printing House for the Blind, 
KW  - Simple machines
KW  - Juvenile literature
N1  - Contracted braille; Transcribed from: Chicago : Benefic Press, 1961
N2  - Describes simple machines--the wedge, screw, wheel, inclined planes, pulley, and lever, and shows how they work
ER  -