@article{PHSC_1998-1999__3_4_279_0,
     author = {de Jongh, Dick and van Ulsen, Paul},
     title = {Beth's nonclassical valuations},
     journal = {Philosophia Scientiae},
     pages = {279--302},
     publisher = {\'Editions Kim\'e},
     volume = {3},
     number = {4},
     year = {1998-1999},
     language = {en},
     url = {http://archive.numdam.org/item/PHSC_1998-1999__3_4_279_0/}
}