Niehaus, F. J. (2001). Karl's diary: Blessed Karl Leisner: in his own words. Schoenstatt Fathers.
Chicago-viite (17. p.)Niehaus, Fr Jonathan. Karl's Diary: Blessed Karl Leisner: In His Own Words. Waukesha, WI: Schoenstatt Fathers, 2001.
MLA-viite (8. p.)Niehaus, Fr Jonathan. Karl's Diary: Blessed Karl Leisner: In His Own Words. Schoenstatt Fathers, 2001.
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