@article{10_4064_fm_122_2_149_157,
     author = {Adam Pio{\l}unowicz},
     title = {On the \ensuremath{\lozenge} principle},
     journal = {Fundamenta Mathematicae},
     pages = {149--157},
     publisher = {mathdoc},
     volume = {122},
     number = {2},
     year = {1984},
     doi = {10.4064/fm-122-2-149-157},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-122-2-149-157/}
}