APA (7th ed.) Citation

Ware, C. F., Panikkar, K. M., & Romein, J. (1966). The twentieth century. Allen and Unwin.

Chicago Style (17th ed.) Citation

Ware, Caroline F., Kavalam Madhava Panikkar, and Jan Romein. The Twentieth Century. London: Allen and Unwin, 1966.

MLA (9th ed.) Citation

Ware, Caroline F., et al. The Twentieth Century. Allen and Unwin, 1966.