@article{AMLG_1975__17_137909,
     author = {Charles G. Morgan},
     title = {Liberated versions of {T,} {S4,} and {S5.}},
     journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
     pages = {85--90},
     publisher = {mathdoc},
     volume = {17},
     year = {1975},
     zbl = {0316.02028},
     url = {http://geodesic.mathdoc.fr/item/AMLG_1975__17_137909/}
}