APA (7th ed.) Citation

Heron-Allen, E. (1921). The purple sapphire: And other posthumous papers. P. Allan.

Chicago Style (17th ed.) Citation

Heron-Allen, Edward. The Purple Sapphire: And Other Posthumous Papers. London: P. Allan, 1921.

MLA (9th ed.) Citation

Heron-Allen, Edward. The Purple Sapphire: And Other Posthumous Papers. P. Allan, 1921.

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