@article{10_4153_CMB_1967_013_3,
     author = {Wong, James S. W.},
     title = {A {Discrete} {Analogue} of {Opial's} {Inequality}},
     journal = {Canadian mathematical bulletin},
     pages = {115--118},
     year = {1967},
     volume = {10},
     number = {1},
     doi = {10.4153/CMB-1967-013-3},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1967-013-3/}
}