Hanger, E. O., & Lowe, P. S. (1937). Directed studies in biology: A combined workbook and labroatory manual. Mentzer, Buch and Co..
Lua i Stíl Chicago (17ú heag.)Hanger, Ernest O., agus Paul S. Lowe. Directed Studies in Biology: A Combined Workbook and Labroatory Manual. New York : Chicago: Mentzer, Buch and Co., 1937.
Lua MLA (8ú heag.)Hanger, Ernest O., agus Paul S. Lowe. Directed Studies in Biology: A Combined Workbook and Labroatory Manual. Mentzer, Buch and Co., 1937.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.