@article{BSL4_2_Blaszczuk_Dziobiak,
author = {Jerzy J. B{\L}ASZCZUK and Wies{\l}aw DZIOBIAK},
title = {Remarks On Perzanowski's Modal System},
journal = {Bulletin of the Section of Logic},
volume = {4},
number = {2},
year = {1975},
pages = {57--64}
}