Lambrecht, L. (1998). Günter Umberg met Bernard Frize, Olivier Mosset, Jo Baer, Fabian Marcaccio, Marte Wéry, David Reed, Helmut Federle, Carl Ostendarp, Elisabeth Vary, Mary Heilmann, Keith Sonnier, Robert Zandvliet mer Vaste collectie Museum Dhondt-Dhaenens.
Trích dẫn kiểu Chicago (xuất bản lần thứ 7)Lambrecht, Luk. Günter Umberg Met Bernard Frize, Olivier Mosset, Jo Baer, Fabian Marcaccio, Marte Wéry, David Reed, Helmut Federle, Carl Ostendarp, Elisabeth Vary, Mary Heilmann, Keith Sonnier, Robert Zandvliet Mer Vaste Collectie Museum Dhondt-Dhaenens. Deurle, 1998.
Trích dẫn kiểu MLA (xuất bản lần thứ 8)Lambrecht, Luk. Günter Umberg Met Bernard Frize, Olivier Mosset, Jo Baer, Fabian Marcaccio, Marte Wéry, David Reed, Helmut Federle, Carl Ostendarp, Elisabeth Vary, Mary Heilmann, Keith Sonnier, Robert Zandvliet Mer Vaste Collectie Museum Dhondt-Dhaenens. 1998.