@article{NSJOM_1988_18_2a_4,
     author = {Acketa Dragan M.},
     title = {A classification of interval greedoids 

 on at most 5 elements},
     journal = {Novi Sad Journal of Mathematics},
     pages = {61-80},
     publisher = {mathdoc},
     volume = {18},
     number = {2},
     year = {1988},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_1988_18_2a_4/}
}