Yazar
c a helm
6 cilt bulundu.
C. A. G. Helm · Universiteit van die Oranje-Vrystaat
385 sayfa · 1979
Blacks / Education / Languages / Native language and education
W. C. Etheridge, C. A. Helm · University of Missouri, College of Agriculture, Agricultural Experiment Station
22 sayfa · 1936
Crop rotation / Lespedeza
W. C. Etheridge, C. A. Helm, B. M. King · University of Missouri, College of Agriculture, Agricultural Experiment Station
14 sayfa · 1930
Lespedeza
W. C. Etheridge, C. A. Helm, B. M. King · University of Missouri, College of Agriculture, Agricultural Experiment Station
51 sayfa · 1929
Soybean / Classification
W. C. Etheridge, C. A. Helm, E. Marion Brown · University of Missouri, College of Agriculture, Agricultural Experiment Station
28 sayfa · 1935
Barley
W. B. Drew, C. A. Helm, University of Missouri. Agricultural Experiment Station · University of Missouri, College of Agriculture
211 sayfa · 1941
Weeds / Control