@article{10_4064_fm_52_3_323_344,
     author = {Leon Henkin},
     title = {A theory of prepositional types},
     journal = {Fundamenta Mathematicae},
     pages = {323--344},
     publisher = {mathdoc},
     volume = {52},
     number = {3},
     year = {1963},
     doi = {10.4064/fm-52-3-323-344},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-52-3-323-344/}
}