B. Baumslag. Photo by Konrad Jacobs.
Additional Information
Picture uploaded by omargosh on Dec 14, 2012.
Copyright: Photo licensed at http://owpdb.mf... by Mathematisches Forschungsinstitut Oberwolfach gGmbH (MFO) under CC-BY-SA 2.0 Germany as noted at http://owpdb.mf...
Grabbed from here.