APA (7th ed.) Citation

(1960). Penguin's progress, 1935-1960. Penguin.

Chicago Style (17th ed.) Citation

Penguin's Progress, 1935-1960. Penguin, 1960.

MLA (9th ed.) Citation

Penguin's Progress, 1935-1960. Penguin, 1960.

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