@article{NSJOM_1999_29_3a_9,
     author = {L. 

 Dovnikovi\'c},
     title = {The 

 realization of the continuity principle in the relativistic pencils of 

 circles and spheres},
     journal = {Novi Sad Journal of Mathematics},
     pages = {97-107},
     year = {1999},
     volume = {29},
     number = {3},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_1999_29_3a_9/}
}