Gustav Siewerths Denkweg: von Thomas von Aquin zu Hegel - Guz, Tadeusz (Vijgen, Jörgen 1974- (edt), Elders, Leo 1926-2019 (hnr), Indubitanter ad veritatem: studies offered to Leo J. Elders SVD in honor of the golden jubilee of his ordination to the priesthood, 2003)