@article{10_4153_CMB_1964_012_x,
     author = {Bullen, P. S.},
     title = {A {New} {Proof} of an {Inequality} of {Heinz}},
     journal = {Canadian mathematical bulletin},
     pages = {97--100},
     year = {1964},
     volume = {7},
     number = {1},
     doi = {10.4153/CMB-1964-012-x},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1964-012-x/}
}