TY  - BOOK
AU  - Shields, Bert A. 
TI  - Principles of Air navigation / 
T2  - The introductory aviation series
U1  - 629.132521 
PY  - 1943///]
CY  - New York, NY : 
PB  - McGraw-Hill Book Company, 
KW  - Navigation (Aeronautics)
N1  - Includes index.
ER  -