APA (7th ed.) Citation

Bondesen, E. (1966). Observations on recent sand volcanoes.

Chicago Style (17th ed.) Citation

Bondesen, Erling. Observations on Recent Sand Volcanoes. Koppenhagen, 1966.

MLA (9th ed.) Citation

Bondesen, Erling. Observations on Recent Sand Volcanoes. 1966.

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