Poṧta, F. The singing double-bass, p2011. (harp)
Prof. Karel Patras Harp Competition. via WWW, January 19, 2016: (Prof. Karel Patras was a noteworthy Czech harpist and teacher of the 20th century; he studied the harp at the State Conservatory and the Academy of Performing Arts in Prague; he played as harpist for the Czech Philharmonic Orchestra from 1945 to 1985)
www.discogs.com, 2019-11-06: Karel Patras. Czech classical harpist and educator at Akademie Múzických Umění/HAMU. Born October 20, 1923 in Přezletice (former Czechoslovakia), died July 29, 2003 in Prague (Czech republic).