@article{JGG_2013_17_1_JGG_2013_17_1_a1,
     author = {D. Ferrarello and M. F. Mammana and M. Pennisi },
     title = {Some {Concyclicity} {Properties} of {Convex} {Quadrilaterals}},
     journal = {Journal for geometry and graphics},
     pages = {7--19},
     publisher = {mathdoc},
     volume = {17},
     number = {1},
     year = {2013},
     url = {http://geodesic.mathdoc.fr/item/JGG_2013_17_1_JGG_2013_17_1_a1/}
}