@article{AFM_2002_27_1_a3,
     author = {Diego Mej{\'\i}a and Christian Pommerenke},
     title = {On the derivative of hyperbolically convex functions},
     journal = {Annales Fennici Mathematici},
     pages = {47--56},
     publisher = {mathdoc},
     volume = {27},
     number = {1},
     year = {2002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AFM_2002_27_1_a3/}
}