@article{JGG_2002_6_1_a4,
     author = {A. Sliepcevic},
     title = {A {New} {Generalization} of the {Butterfly} {Theorem}},
     journal = {Journal for geometry and graphics},
     pages = {061--068},
     publisher = {mathdoc},
     volume = {6},
     number = {1},
     year = {2002},
     url = {http://geodesic.mathdoc.fr/item/JGG_2002_6_1_a4/}
}