Obourn, E. S., & Heiss, E. D. (1936). Modern science problems: A textbook in general science. Webster Pub. Co..
Lua i Stíl Chicago (17ú heag.)Obourn, Ellsworth Scott, agus Elwood D. Heiss. Modern Science Problems: A Textbook in General Science. St. Louis, Mo.: Webster Pub. Co., 1936.
Lua MLA (8ú heag.)Obourn, Ellsworth Scott, agus Elwood D. Heiss. Modern Science Problems: A Textbook in General Science. Webster Pub. Co., 1936.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.