Charles Robert Richet

Traité de métapsychique

F. Alcan, Paris 1922.

Journal of the Society for Psychical Research

Vol. 21, London 1923.

Proceedings of the Society for Psychical Research

Vol. 33, London 1923.

Proceedings of the Society for Psychical Research

Vol. 34, London 1924.

Jules Romains

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

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