TY  - BOOK
AU  - Tinbergen J
AU  - Klaassen L H
AU  - Mulder E H
TI  - Observation on the planned provision of nitrogen fertilizer or the world
U1  - 631.84 
PY  - 1956///
CY  - Leiden
PB  - H E Stenfert Kroese N V
KW  - Nitrogenous fertilizers
ER  -