@article{SMJ2_2007_33_1_a1,
     author = {Manchev, Peter},
     title = {Oligopoly {Model} of a {Debit} {Card} {Network}},
     journal = {Serdica Mathematical Journal},
     pages = {35--46},
     publisher = {mathdoc},
     volume = {33},
     number = {1},
     year = {2007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SMJ2_2007_33_1_a1/}
}