@article{PORMA_1987__44_2_115582,
     author = {Mazhar, S.M. and Al-Budaiwi, Aisha},
     title = {A note on a {Theorem} of {Ermakov}},
     journal = {Portugaliae mathematica},
     pages = {213--219},
     publisher = {mathdoc},
     volume = {44},
     number = {2},
     year = {1987},
     mrnumber = {0911443},
     zbl = {0636.42004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1987__44_2_115582/}
}