Zurich, 12 December 1955 - Institutional correspondence A letter from Klaus Herdeg to Willem Sandberg
Edinburgh, 25 January 1939 - Institutional correspondence Elizabeth Watt's letter to J.N. Duddington, dated 25 January 1939
Edinburgh, 7 April 1939 - Institutional correspondence Elizabeth Watt 's letter to J.N. Duddington, dated 7 April 1939