Auderset, Juri: Wiegner, GeorgHistorischen Lexikon der Schweiz. Viitattu 30.1.2016. (saksaksi)
iuss.org
Sticher, Hans: Soil Science and Soil Scientists in Switzerland (1855 – 1962) (pdf) (uutiskirje, s. 13) Committee on the History, Philosophy, and Sociology of Soil Science International Union of Soil Sciences And Council on the History, Philosophy, and Sociology of Soil Science Soil Science Society of America. Arkistoitu 23.6.2006. Viitattu 30.1.2016. (englanniksi)
web.archive.org
Sticher, Hans: Soil Science and Soil Scientists in Switzerland (1855 – 1962) (pdf) (uutiskirje, s. 13) Committee on the History, Philosophy, and Sociology of Soil Science International Union of Soil Sciences And Council on the History, Philosophy, and Sociology of Soil Science Soil Science Society of America. Arkistoitu 23.6.2006. Viitattu 30.1.2016. (englanniksi)