Topsy and Eva [MP] 1927 credits (The Duncan Sisters in)
Variety obituaries, 1984-1986 10/15/86 (Vivian Duncan; with her sister performed as The Duncan Sisters; sometimes billed as the Heavenly Twins)
Internet Broadway database, October 2, 2012 (The Duncan Sisters; Composer, Lyricist; Female; Primary Organization Members: Rosetta Duncan and Vivian Duncan)