Crystallographic Evidence for Preformed Dimers of Erythropoietin Receptor Before Ligand Activation Livnah, Oded ; Stura, Enrico A. ; Middleton, Steven A. ; Johnson, Dana L. ; Jolliffe, Linda K. ; Wilson, Ian A. Abstract Publication: Science Pub Date: February 1999 DOI: 10.1126/science.283.5404.987 Bibcode: 1999Sci...283..987L