Pages 82-83 in Extension Circular 541, Review of Extension Research, January through December 1961, U.S. Department of Agriculture, Washington, D.C. Summary of research, Baltimore City Extension Service, Baltimore, Maryland. 1961. 26 pages.
Page 64-65 in Review of Extension Research, January through December 1957. Survey for Agricultural Extension, University of California, Berkeley. 1957. 8 pages.
Page 60 in Extension Circular 541, Review of Extension Research, January through December 1961, U.S. Department of Agriculture, Washington, D.C. Summary of Ohio Agricultural Experiment Station Research Bulletin 890 of this title, Ohio State University, Wooster. 1961. 18 pages.