Alfredo Buttari Pasqua D'Ambra Daniela di Serafino Salvatore Filippone Extending PSBLAS to Build Parallel Schwarz Preconditioners. 593-602 2004 conf/para/2004 PARA http://dx.doi.org/10.1007/11558958_71 db/conf/para/para2004.html#ButtariDSF04