Joel Berman Wieslaw Dziobiak Don Pigozzi James G. Raftery In Memory of Willem Johannes Blok 1947-2003. 5-14 2006 83 Studia Logica 1-3 http://dx.doi.org/10.1007/s11225-006-8295-3 db/journals/sLogica/sLogica83.html#BermanDPR06