@article{10_21136_MB_1992_126283,
     author = {Jakub{\'\i}k, J\'an},
     title = {On projective intervals in a modular lattice},
     journal = {Mathematica Bohemica},
     pages = {293--298},
     publisher = {mathdoc},
     volume = {117},
     number = {3},
     year = {1992},
     doi = {10.21136/MB.1992.126283},
     mrnumber = {1184542},
     zbl = {0773.06013},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/MB.1992.126283/}
}