APA (7th ed.) Citation

Hebblethwaite, P. (1978). The year of three popes. Collins.

Chicago Style (17th ed.) Citation

Hebblethwaite, Peter. The Year of Three Popes. London [etc.]: Collins, 1978.

MLA (9th ed.) Citation

Hebblethwaite, Peter. The Year of Three Popes. Collins, 1978.

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