Jules Romains

Eyeless Sight: A Study of Extra-Retinal Visoin and the Paroptic Sense

G. P. Putnam's Sons, London 1924.

Jean Audry

Le mesmérisme et le somnambulisme à Lyon avant la Révolution

Mémoires de l'Académie des Sciences, Belles-Lettres et Arts de Lyon, Vol. 18, 1924, pp. 57-101.

G.B. Seybold

They Can See with Their Skin

Popular Science Monthly, dicembre 1925, p. 21.