APA (7th ed.) Citation

Stevenson, R. L., & Harper, H. H. Robert Louis Stevenson: Hitherto unpublished prose writings.

Chicago Style (17th ed.) Citation

Stevenson, Robert Louis, and Henry Howard Harper. Robert Louis Stevenson: Hitherto Unpublished Prose Writings.

MLA (9th ed.) Citation

Stevenson, Robert Louis, and Henry Howard Harper. Robert Louis Stevenson: Hitherto Unpublished Prose Writings.

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