TY  - BOOK
AU  - Twito,Roger H.
AU  - Mann,Charles N.
ED  - United States.
TI  - Determining average distance
U1  -  629.132520973 
PY  - 1979///
CY  - Washington, D.C.
PB  - U.S. Government Printing Office
KW  - Air traffic control
KW  - United States
KW  - Aids to air navigation
KW  - Air-pilot guides
N1  - General technical report no. PNW-79; Forest service; Pacific North West forest and range experiment station
ER  -