1 http://hdl.handle.net/10338.dmlcz/116846 1 Summaries of articles published in this issue http://hdl.handle.net/10338.dmlcz/101456 Summaries of articles published in this issue Mon, 09 Jun 2008 14:22:32 GMT News and Notices http://hdl.handle.net/10338.dmlcz/101455 News and Notices Mon, 09 Jun 2008 14:22:27 GMT Tolerance relations on periodic commutative semigroups http://hdl.handle.net/10338.dmlcz/101454 Tolerance relations on periodic commutative semigroups Mon, 09 Jun 2008 14:22:23 GMT Generation of preradicals http://hdl.handle.net/10338.dmlcz/101453 Generation of preradicals Mon, 09 Jun 2008 14:22:18 GMT