Nuttonson, M. Y. (1955). Wheat-climate relationships and the use of phenology in ascertaining the thermal and photo-thermal requirements of wheat - Based on data of North America and of some thermally analogous areas of North America in the Soviet Union and in Finland. Washington, D. C.: American Institute of Crop Ecology.

Nuttonson, M. Y. Wheat-climate Relationships and the Use of Phenology in Ascertaining the Thermal and Photo-thermal Requirements of Wheat - Based On Data of North America and of Some Thermally Analogous Areas of North America in the Soviet Union and in Finland. Washington, D. C.: American Institute of Crop Ecology, 1955.

Nuttonson, M. Y. Wheat-climate Relationships and the Use of Phenology in Ascertaining the Thermal and Photo-thermal Requirements of Wheat - Based On Data of North America and of Some Thermally Analogous Areas of North America in the Soviet Union and in Finland. Washington, D. C.: American Institute of Crop Ecology, 1955.