@article{BSL_2020_49_3_a1,
     author = {Niki, Satoru},
     title = {Empirical {Negation,} {Co-negation} and {Contraposition} {Rule} {I:} {Semantical} {Investigations}},
     journal = {Bulletin of the Section of Logic},
     pages = {231--253},
     publisher = {mathdoc},
     volume = {49},
     number = {3},
     year = {2020},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/BSL_2020_49_3_a1/}
}