Johnson, M. L. P. (1974). Thirty years with an idea. University of Alabama Press for the Organic School.
Chicago-referens (17:e uppl.)Johnson, Marietta Louise Pierce. Thirty Years with an Idea. University: University of Alabama Press for the Organic School, 1974.
MLA-referens (9:e uppl.)Johnson, Marietta Louise Pierce. Thirty Years with an Idea. University of Alabama Press for the Organic School, 1974.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.