Agriculture in Ohio Elementary Schools. A Manual for Teachers of Grades Seven and Eight; Prepared by F. E. Heald and Alvin Dille, in Cooperation with the Ohio State Department of Public Instruction and the College of Agriculture, Ohio State University. Pub. by State Department of Public Instruction. F. B. Pearson, Supt.Ohio. Dept. of Education1919EN
Experiments in plant physiology, by Frederick De Forest Heald and Isaac McKinney Lewis.F. Heald1910EN