Dyfyniad APA

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

Dyfyniad Arddull Chicago

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

Dyfyniad MLA

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

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.