Langley, J. A., Heady, E. O., & Huang, W. Y. (1981). A recursive adaptive hybrid model for the analysis of the national and interregional impacts of three alternative agricultural situations for 1981-83. Ames: Center for Agricultural and Rural Development. Iowa State University.

Langley, James A., Earl O. Heady, and Wen Yuan Huang. A Recursive Adaptive Hybrid Model for the Analysis of the National and Interregional Impacts of Three Alternative Agricultural Situations for 1981-83. Ames: Center for Agricultural and Rural Development. Iowa State University, 1981.

Langley, James A., Earl O. Heady, and Wen Yuan Huang. A Recursive Adaptive Hybrid Model for the Analysis of the National and Interregional Impacts of Three Alternative Agricultural Situations for 1981-83. Ames: Center for Agricultural and Rural Development. Iowa State University, 1981.