TY  - BOOK
AU  - Windle,Eric
AU  - Kaufmann,John
TI  - Sounds you cannot hear
T2  - P-H junior research books
AV  - QC244 .W56
U1  - 534.5/5 
PY  - 1963///]
CY  - Englewood Cliffs, N.J.
PB  - Prentice-Hall
KW  - Ultrasonics
KW  - Juvenile literature
KW  - Sound
N2  - Explains the principles of sound, ultrasonic sound, radar, and sonar and discusses how certain birds and fish use ultrasonics to guide them
UR  - http://www.archive.org/details/soundsyoucannoth00wind
UR  - http://www.openlibrary.org/books/OL5879261M
ER  -