Cook, R. C., & Lecht, J. (1968). People!: An introduction to the study of population. Columbia Books.
Lua i Stíl Chicago (17ú heag.)Cook, Robert C., agus Jane Lecht. People!: An Introduction to the Study of Population. Washington: Columbia Books, 1968.
Lua MLA (9ú heag.)Cook, Robert C., agus Jane Lecht. People!: An Introduction to the Study of Population. Columbia Books, 1968.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.