TY  - BOOK
AU  - Spedding,C.R.W.
AU  - Walsingham,J.M.
AU  - Hoxey,A.M.
TI  - Biological efficiency in agriculture
U1  - 630 
PY  - 1981///
CY  - London, New York
PB  - Academic Press
KW  - Agricultural productivity
KW  - Biological productivity
KW  - Agriculture
KW  - Biology, Economic
ER  -