1. COYLER, D. and GEORGE IRWIN. Beef, Pork and Feed Grains in the Cornbelt: Supply Response and Resource Adjustment. University of Missouri, Agricultura! Experiment Station, Research Bulletin 921, Aug. 1967.

2. CROMARTY, WILLIAM A. The Farm Demand for Tractors, Machinery and Trucks. Journal of Farm Economics, Vol. 41. Feb. Aug. 1959. pp. 323-331.

3. DAY, R. H. Recursive Programming and Production Response. Amsterdan: North-Holland, 1963.

4. FETTIG, L. P. Purchases of New Farm Tractores and Machinery in Relation to the Non-Farm Business Cycles. Unpublished MS Thesis. Michigan State University, 1958.

5. FETTIG, L. P. Adjusting Farm Tractor Prices for Quality Changes, 1959-1962. Journal of Farm Economics. 1963. pp. 599-611.

6. FOX, AUSTIN. Demand for Farm Tractor-Power in the United States, USDA, 1964, cited by MINDEN (14).

7. GRILICHES, ZVI. The Demand for Inputs in Agriculture and a Derived Supply Elasticity. Journal of Farm Economics, Vol. 41, Feb-Aug. 1959, pp. 309-322.

8. GRILICHES, ZVI. The Demand for Durable Inputs: Farm Tractors in the United States. 1921-1957. ln Harberger, Arnold C., "The Demand ed. for Durable goods", pp. 181-207. University of Chicago Press, 1960.

9. GRILICHES, ZVI. Hedonic Prices Indexes Revisited: Some Notes on the State of the Art. Center for Mathematical Studies in Business and Economics. Report 6802, January 1968.

10. HATHAWAY, D. E. Agriculture and Business Cycle in U.S. Congress Joint Economic Committee. "Policy for Comercial Agriculture". 1957.

11. HEADY, EARL O. and LUTHER G. TEEETEN. Resource Demand and Structure of the Agricultura! Industry. Iowa State University Press, 1963.

12. KALDOR, M. Mr. Hicks and the Trade Cycle. Economic Journal, Vol. 61. 1961 pp. 833-84 7.

13. KLEIN, LAURENCE. Studies in Investment Behavior in Conference of Business Cycles. National Bureau of Economic Research, Inc. 1951.

14. MINDEN, ARLO J. Domestic Demand Functions for New Farm Machinery. Unpublished Phd Thesis. Iowa Sta te University, 1965.

15. SCOTT, JOHN T. The Economic Variables of lnvestment. A preliminary Paper for UDSA Farm Building Project. Iowa State University, 1963.

16. SHARPLES. JERRY A .. TOMAS A, MILLER and LEEM. DAY. Evaluation of a Firm Model in Estimating Aggregate Supply Response. NCRR Publication 179, Jan. 1968. Agriculture and Home Economics Experiment Station, Iowa State University, Research Bulletin 558.