@article{MAN_1990__286_1-3_164659,
     author = {YoungJu Choie and L. Alayne Parson},
     title = {Rational period functions and indefinite binary quadratics forms. {I.}},
     journal = {Mathematische Annalen},
     pages = {697--708},
     publisher = {mathdoc},
     volume = {286},
     number = {1-3},
     year = {1990},
     zbl = {0673.10018},
     url = {http://geodesic.mathdoc.fr/item/MAN_1990__286_1-3_164659/}
}