TY  - BOOK
AU  - Collings, Gilbeart Hooper.
TI  - Commercial fertilizers: : their sources and use
T2  - Blakiston books on agriculture
U1  - 631.8 
PY  - 1941///
CY  - Philadelphia
PB  - Blakiston
KW  - Suelos
KW  - Fertilidad
ER  -