@article{ Solr-acta15151, title = {Structure-filters in equality-free model theory}, series = {Acta scientiarum mathematicarum}, author = {Ecsedi-Tóth Péter}, year = {1987}, url = {http://acta.bibl.u-szeged.hu/15151/1/math_051_fasc_003_004_387-402.pdf} }