@article{10_4064_ap_19_1_69_79,
     author = {J. C. Merlo},
     title = {On orthogonal polynomials and second-order linear differential operators},
     journal = {Annales Polonici Mathematici},
     pages = {69--79},
     publisher = {mathdoc},
     volume = {19},
     number = {1},
     year = {1967},
     doi = {10.4064/ap-19-1-69-79},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-19-1-69-79/}
}