TY  - BOOK
AU  - WILLIAM L. ALLEN EDITOR ETC
TI  - NATIONAL GEOGRAPHIC DECEMBER 1999
T2  - VOL. 196 NO.6 1999
U1  - 050.8 NG v.12 1999 
PY  - 1999///
CY  - 
PB  - NATIONAL GEOGRAPHIC SOCIETY
KW  - 连续性出版品; 期刊--NATIONAL GEOGRAPHIC
ER  -