@article{10_4064_ap_58_3_237_252,
     author = {J. Macura and J. \'Sladkowska},
     title = {On functions satisfying more than one equation of {Schiffer} type},
     journal = {Annales Polonici Mathematici},
     pages = {237--252},
     publisher = {mathdoc},
     volume = {58},
     number = {3},
     year = {1993},
     doi = {10.4064/ap-58-3-237-252},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-58-3-237-252/}
}