@article{NCD_2004_4_a0,
     author = {Milena Dobreva and Nikola Ikonomov},
     title = {Preface},
     journal = {Review of the National Center for Digitization},
     pages = {2 },
     year = {2004},
     volume = {4},
     url = {http://geodesic.mathdoc.fr/item/NCD_2004_4_a0/}
}