APA (7th ed.) Citation

Sinclair, U. (1937). No pasaran!: (They shall not pass). A story of the siege of Madrid. Publ. by the author.

Chicago Style (17th ed.) Citation

Sinclair, Upton. No Pasaran!: (They Shall Not Pass). A Story of the Siege of Madrid. Pasadena, Calif: Publ. by the author, 1937.

MLA (9th ed.) Citation

Sinclair, Upton. No Pasaran!: (They Shall Not Pass). A Story of the Siege of Madrid. Publ. by the author, 1937.

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