@article{ Solr-acta16335, title = {Existentially definable factor congruences}, series = {Acta scientiarum mathematicarum}, author = {Sánchez Terraf Pedro}, year = {2010}, url = {http://acta.bibl.u-szeged.hu/16335/1/math_076_numb_001_002_049-053.pdf} }