ལྷ་སར་ཡོང་བའི་འཇར་མན་པ་ཐོག་མ་ཨེན་སི་ཐེ་ཏྲེ་ཧཕེར་དང་ཁོང་གི་ཐསན་རིག་རྟོག་ཞིག་ཚོགས་པ།, ཀྲའོ་ཀུང་རུའེ།; see BDRC (W3CN25663), vol. 2, pp. 615-629
"Schäfer collection":http://www.loc.gov/pictures/item/2010651980/ at the Library of Congress with ca. 35,000 items (accessed: 2016-06-16)
Ernst Schäfer files (Notes or journal of a Deutsche Tibet Expedition, 1938-1939) at the Library of Congress, box 828, reel 491-492; cf. "German Captured Documents Collection:A Finding Aid to the Collection in the Library of Congress Manuscript Division, Library of Congress, [revised 2012 October]":hdl.loc.gov/loc.mss/eadmss.ms011148.3, p. 108 (accessed: 2016-06-16). Schäfer's unpublished and hand-written notes kept in the manuscript division at the Library of Congress are also referred to by Isrun Engelhardt (1941–2022), Mishandled Mail: The Strange Case of the Reting Regent’s Letters to Hitler (Online version on "Tibetan Buddhism in the West":http://info-buddhism.com/index.html), note 5 (accessed: 2016-06-16)