Exploration of the Colorado River and the High Plateaus ofUtah by the Second Powell Expedition of 1871–1872. Salt Lake City: University ofUtah Press. 2009
(原始内容存档于2020-12-25). Norum KR, Grav HJ. [Axel Holst and Theodor Frolich--pioneers in the combat of scurvy]. Tidsskrift for den Norske Laegeforening. June 2002, 122