@article{JGG_2006_10_1_JGG_2006_10_1_a2,
     author = {D. Papadopoulou and P. Koltsaki},
     title = {On a {Special} {Pair} of {Parallel} {Congruences}},
     journal = {Journal for geometry and graphics},
     pages = {23--36},
     year = {2006},
     volume = {10},
     number = {1},
     url = {http://geodesic.mathdoc.fr/item/JGG_2006_10_1_JGG_2006_10_1_a2/}
}