APA (7th ed.) Citation

(1940). [Postcard from George Bernard Shaw to Sean O'Casey. 4 Whitehall Court, London, and Ayot St. Lawrence. April 22, 1940].

Chicago Style (17th ed.) Citation

[Postcard from George Bernard Shaw to Sean O'Casey. 4 Whitehall Court, London, and Ayot St. Lawrence. April 22, 1940]. London, 1940.

MLA (9th ed.) Citation

[Postcard from George Bernard Shaw to Sean O'Casey. 4 Whitehall Court, London, and Ayot St. Lawrence. April 22, 1940]. 1940.

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