@article{RCM_1987__21_1_181775,
     author = {E.P. Merkes},
     title = {On {The} {Convex} {Sum} {Of} {Certain} {Univalent} {Functions} {And} {The} {Identity} {Function.}},
     journal = {Revista colombiana de matematicas},
     pages = {5--12},
     year = {1987},
     volume = {21},
     number = {1},
     zbl = {0655.30010},
     url = {http://geodesic.mathdoc.fr/item/RCM_1987__21_1_181775/}
}