TY  - BOOK
AU  - Levitt J
TI  - Hardiness of plants
T2  - American Society of agronomy
U1  - I:55, J6 
PY  - 1956///
CY  - New York    
PB  -  Academic Press       
KW  -  Plant ecology
KW  - Botany
N1  - References 230-274p
ER  -