Johnson, Donald M., and Leon G. Schumacher. “Agricultural Mechanics Specialists Identification and Evaluation of Agricultural Mechanics Laboratory Management Competencies: A Modified Delphi Approach”. Journal of Agricultural Education 30, no. 3 (September 30, 1989): 23–28. Accessed August 21, 2026. https://jae-online.org/index.php/jae/article/view/1559.