\bibstyle{alpha} \bibdata{sonata} \citation{thomaswood80:GT} \citation{scott69:TAOPMOAGATSOCPPGI} \citation{ecker98:OTNOPFONGOC2} \citation{Pilz:Nearrings} \citation{meldrum85:NATLWG} \citation{Clay:Nearrings} \citation{Pilz:Nearrings} \citation{meldrum85:NATLWG} \citation{Clay:Nearrings} \citation{aichingereckernoebauer00:TUOCINT} \citation{aichingerea00:CWN} \citation{Pilz:Nearrings} \citation{meldrum85:NATLWG} \citation{Clay:Nearrings} \citation{Wolf:Spaces} \citation{Mayr:Representations} \citation{Waehling:Fastkoerper} \citation{Clay:Nearrings} \citation{Clay:Nearrings} \citation{Clay:Nearrings} \citation{Clay:Nearrings}