@article{NSJOM_1988_18_1a_6,
     author = {Acketa Dragan M.},
     title = {All interval greedoids on at most 5 

 elements},
     journal = {Novi Sad Journal of Mathematics},
     pages = {69-76},
     publisher = {mathdoc},
     volume = {18},
     number = {1},
     year = {1988},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_1988_18_1a_6/}
}