Gaya APA

Greenland, D., J, I, D, B, H. (NULL). The earth in profile aphysical geography . San: San Francisco: Canfield Press; 1977.

Gaya MLA

Greenland, David., J, I., De, Blij,, Harm. "The earth in profile aphysical geography". San: San Francisco: Canfield Press; 1977, NULL. Text.