APA (7th ed.) Citation

Levring, T., Hoppe, H. A., & Schmidt, O. J. (1969). Marine algae: A survey of research and utilization. de Gruyter.

Chicago Style (17th ed.) Citation

Levring, Tore, Heinz August Hoppe, and Otto J. Schmidt. Marine Algae: A Survey of Research and Utilization. Hamburg: de Gruyter, 1969.

MLA (9th ed.) Citation

Levring, Tore, et al. Marine Algae: A Survey of Research and Utilization. de Gruyter, 1969.