APA (7th ed.) Citation

Heider, K. G. (1961). Tikal. Documentary Educational Resources (DER).

Chicago Style (17th ed.) Citation

Heider, Karl G. Tikal. Watertown (Mass.): Documentary Educational Resources (DER), 1961.

MLA (9th ed.) Citation

Heider, Karl G. Tikal. Documentary Educational Resources (DER), 1961.

Warning: These citations may not always be 100% accurate.