TY  - BOOK
AU  - Beck,Charles B.
TI  - Origin and evolution of gymnosperms / 
U1  - 561.5 21
PY  - 1988///
CY  - Dehra Dun : 
PB  - Bishen Singh Mahendra Pal Singh , 
KW  - GYMNOSPERMS - ORIGIN
KW  - GYMNOSPERMS - FOSSIL
KW  - GYMNOSPERMS - EVOLUTION
KW  - PALEOBOTANY
N1  - Includes bibliographical referrences and index
ER  -