Ward, C. H. (1923). Exploring nature. H. Holt and Co.
Lua i Stíl Chicago (17ú heag.)Ward, C. H. Exploring Nature. New York: H. Holt and Co, 1923.
Lua MLA (8ú heag.)Ward, C. H. Exploring Nature. H. Holt and Co, 1923.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.