TY  - REP
AU  - Barker,R.
AU  - Alberto Valdes
AU  - Gabler,E.C.
AU  - Winkelmann,D.
TI  - Long-term consequences of technological change on crop yield stability:  the case for cereal grain
PY  - 1981///
N1  - Includes references p. 76-78
ER  -