LCCN 72156623: Burnham, W.H. Great teachers and mental health, 1971 (505 field: Trotzendorf, pioneer in social pedagogy)
LCCN ltf91038986: Weigl, F.X. Valentin Trotzendorf und seine Zeitgenossen, 194-.
Lobies, J. IBN, 1973- : pars C, v. 77, p. 523 (hdg.: Friedland, Valentin; surname variants: Trotzendorf, Trocedorfius, Troitschendorf, Trozendorf; b. 1490, Troitschendorf; d. 1556 Liegnitz)
Rosarium scholae Trocedorfii, 1565: t.p. (... Trocedorfii)
WBIS, Sept. 24, 2008 (Trotzendorf, Valentin Friedland; also Walentin Trocedorf; b. 1490; d. 1556)
Wikipedia, Sept. 24, 2008 (Valentin Friedland; also called Valentin Troitschendorf (or Trozendorf or Trotzendorf); b. Feb. 14, 1490, Troitschendorf, Germany; d. Apr. 26, 1556, Liegnitz)