- Rachel Dickson, ''I hear only what my eyes tell me': Two Jewish Women Émigré Sculptors: Else Fraenkel (1892-1975) and Erna Nonnenmacher (1889-1989)', PMSA - Public Monuments and Sculpture Association and 3rd Dimension Annual Conference (2016), Émigré Sculptors in Britain (1500-2016) (unpublished conference paper, 2017)
- Jutta Vinzent, 'List of Refugee Artists (Painters, Sculptors, and Graphic Artists) From Nazi Germany in Britain (1933-1945)' in Identity and Image: Refugee Artists from Nazi Germany in Britain (1933-1945) (Kromsdorf/Weimar: VDG Verlag, 2006) pp. 249-298
- Hans Hildebrandt, Die Frau als Künstlerin (Berlin: Rudolf Mosse Buchverlag, 1928) p. 184