From the artist to his studio assistant
W. A. Ewing, Blumenfeld Photographs: A Passion for Beauty, New York: Abrams, 1996, pl. 44 for a variant, there dated 1936
Erwin Blumenfeld: Paintings, Drawings, Collages & Photographs, San Francisco, CA: Modernism, 2006, p. 48 for a variant, there dated 1936