Twelve artists from the German Democratic Republic : Gerhard Altenbourg, ... Thomas Ziegler ; catalogue for an exhibition ; [september 16 - november 5, 1989, Busch-Reisinger Museum, Harvard Univ., Cambridge, [...] / organized by the Busch-Reisinger Museum, Harvard University. Ed. and introd. by Peter Nisbet. With contributions from Doré Ashton ... Cambridge, Mass. : Harvard Univ., Busch-Reisinger Museum, 1989