”Resumè 1966 – 1999 - Heidi Guthmann Birck Aage Birck - Skulptur

 Unika” by art critic and art historian Lisbeth Tolstrup with preface by

 Birgit Jenvold, curator at Museet på Koldinghus, Kolding and

Peter-Winfried Bürkner, derector of Keramion – Museum für

 zeitgenössische Kunst, Frechen, Germany.

ISBN: 87-21-01232-6, Borgens Forlag, Copenhagen – 1999.