^True, Alfred Charles (1937). A History of agricultural experimentation and research in the United States, 1607-1925 (1 ed.). Washington: Government Printing Office. pp. 52–53. OCLC458404288.
^Hutchinson, Sir Joseph, F.R.S. (1984). "Sydney Cross Harland". Biographical Memoirs of Fellows of the Royal Society. 30: 299. JSTOR769829.{{cite journal}}: CS1 maint: multiple names: authors list (link)