@article{PIM_1980_N_S_27_41_a22,
     author = {{\DJ}uro Kurepa},
     title = {On [m, {n]-Ramifications} {Or} [m, {n]-Pseudo-Trees} {Of} {Sets}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {143 },
     publisher = {mathdoc},
     volume = {_N_S_27},
     number = {41},
     year = {1980},
     url = {http://geodesic.mathdoc.fr/item/PIM_1980_N_S_27_41_a22/}
}