Ernst Bjerknes (1944). "Skiløbning i 80 årene"(PDF). Excerpt from "Med ski, velosiped og skissebok", Jacob Dybwads Forlag, Oslo 1944. Reprinted in "Vindern Historielags medlemsblad 47" (2003) (in Norwegian). pp. 20–24. Archived from the original(PDF) on 2007-02-25. Retrieved 2008-10-04.
Ernst Bjerknes (1944). "Skiløbning i 80 årene"(PDF). Excerpt from "Med ski, velosiped og skissebok", Jacob Dybwads Forlag, Oslo 1944. Reprinted in "Vindern Historielags medlemsblad 47" (2003) (in Norwegian). pp. 20–24. Archived from the original(PDF) on 2007-02-25. Retrieved 2008-10-04.