@article{GDZPPN002043750, title = {Decision procedures for S3... and S4.. .}, journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung}, volume = {12}, year = {1969}, pages = {155-158}, url = {http://dml.mathdoc.fr/item/GDZPPN002043750} }
Zeman, J. Jay. Decision procedures for S3... and S4.. .. Archiv für mathematische Logik und Grundlagenforschung, Tome 12 (1969) pp. 155-158. http://gdmltest.u-ga.fr/item/GDZPPN002043750/