TY  - BOOK
AU  - Frost,A.
TI  - The principles and practice of navigation / 
SN  - 9780851745428 
U1  - 623.89 23
PY  - 1993///.
CY  - Glasgow : 
PB  - Brown, Sons & Ferguson, 
KW  - Navigation.
KW  - Seamanship -- Celestial navigation - Manuals.
ER  -