APA

Estados Unidos, Guither H. D., Jones B. F., Martin M. A. & Spitze R. G. F. (1989). U. S. farmers' preferences for agricultural and food policy in the 1990s. Illinois: North Central Public Policy Education Committee.

Chicago

Estados Unidos, Guither Harold D, Jones Bob F, Martin Marshall A and Spitze Robert G F. 1989. U. S. farmers' preferences for agricultural and food policy in the 1990s. Illinois: North Central Public Policy Education Committee.

Harvard

Estados Unidos, Guither H. D., Jones B. F., Martin M. A. and Spitze R. G. F. (1989). U. S. farmers' preferences for agricultural and food policy in the 1990s. Illinois: North Central Public Policy Education Committee.

MLA

Estados Unidos, Guither Harold D, Jones Bob F, Martin Marshall A and Spitze Robert G F. U. S. farmers' preferences for agricultural and food policy in the 1990s. Illinois: North Central Public Policy Education Committee. 1989.