Letter from Captain W. McPherson to Tinbergen's mother, Aberdeen, 4 November 1932; postcard from the Grønlands Styrelse, Copenhagen, 9 November 1932; letter from Tinbergen to his family, 23 August 1932 (delivered in an envelope postmarked Copenhagen 18 November 1932 and stamped Grønlands Styrelse); 'Brief-Telegram ontvangen 22-11-'32'.