@article{oai:ir.kagoshima-u.ac.jp:00010046, author = {KAWAI, Toru and 河合, 徹}, journal = {鹿児島大学理学部紀要. 数学・物理学・化学, Reports of the Faculty of Science, Kagoshima University. Mathematics, physics, chemistry}, month = {Dec}, pages = {37--42}, title = {AN AXIOM SYSTEM FOR NONSTANDARD SET THEORY}, volume = {12}, year = {1979} }