@unpublished{HoppePetrova2007,
  author  = {Ronald H. W. Hoppe and Svetozara I. Petrova},
  title   = {On the return mapping algorithms in structural optimization of biomorphic ceramics},
  institution = {Mathematisch-Naturwissenschaftlich-Technische Fakult{\"a}t},
  series    = {Preprints des Instituts f{\"u}r Mathematik der Universit{\"a}t Augsburg},
  number    = {2007-19},
  year    = {2007},
}