Lua APA (7ú heag.)

Helgren, D. M., & Sager, R. J. (1995). World geography today. Holt, Rinehart and Winston.

Lua i Stíl Chicago (17ú heag.)

Helgren, David M., agus Robert J. Sager. World Geography Today. Austin, TX: Holt, Rinehart and Winston, 1995.

Lua MLA (9ú heag.)

Helgren, David M., agus Robert J. Sager. World Geography Today. Holt, Rinehart and Winston, 1995.

Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.