Ouders en homosexualiteit / [samenst.: Freek Rhebergen ... et al. ; Herman Roose (tekst)]Ordovicische zwerfsteensponzen / Freek Rhebergen (red.) ... [et al.]A new Late Ordovician erratic anthaspidellid sponge (Porifera) originating from Baltica / F. Rhebergen $ Miocene bryozoa from East Kalimantan, Indonesia : part I: cyclostomata and 'anascan' cheilostomata / E. Di Martino & P.D. Taylor