@article{NSJOM_1992_22_2a_2,
     author = {Petrovi\'c Nenad},
     title = {On a difference scheme 

 for singular perturbation problems},
     journal = {Novi Sad Journal of Mathematics},
     pages = {23-37},
     year = {1992},
     volume = {22},
     number = {2},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_1992_22_2a_2/}
}