As the sorting process began I very soon relocated the paper about the Lowenfeld Sand Tray 'World' Material by Ruth Pickford.  There is more about the paper in the book BALANCING THE REQUEST TO BE GOOD: Chapter 2 The Miraculous Leaflet.

Whilst the work, as I understand it, began with my experiences in Masset and Old Masset it was the accidental discovery of this paper which awakened in me the kind of interest that eventually resulted in the development of CUSTTAD. Without that paper I am certain it would never have happened. 

Expression of Thoughts by Means of the Lowenfeld Sand Tray 'World' Material.

Transcultural Aspects of Psychiatric Art, ed.I Jakab, Psychiatry and Art, vol. 4 pp,188-192 (Karger, Basel 1975)