@article{JGG_2014_18_1_JGG_2014_18_1_a1,
     author = {C.-S. Barbat },
     title = {A {Generalization} of {Ivory's} {Theorem}},
     journal = {Journal for geometry and graphics},
     pages = {7--21},
     publisher = {mathdoc},
     volume = {18},
     number = {1},
     year = {2014},
     url = {http://geodesic.mathdoc.fr/item/JGG_2014_18_1_JGG_2014_18_1_a1/}
}