@article{10_1017_S0017089500003712,
     author = {Feinerman, Robert},
     title = {Triple orthogonal series},
     journal = {Glasgow mathematical journal},
     pages = {49--53},
     year = {1979},
     volume = {20},
     number = {1},
     doi = {10.1017/S0017089500003712},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500003712/}
}