@article{AFM_1972_501-520_a5,
     author = {Aatos Lahtinen},
     title = {On the solutions of {\ensuremath{\Delta}u} = {Pu} for acceptable densities on open {Riemann} surfaces},
     journal = {Annales Fennici Mathematici},
     publisher = {mathdoc},
     volume = {501-520},
     year = {1972},
     doi = {10.5186/aasfm.1972.515},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.5186/aasfm.1972.515/}
}