@article{700073,
     title = {Finite element methods for elliptic mixed boundary value problems containing singularities},
     booktitle = {Proceedings of Equadiff III},
     series = {GDML\_Books},
     publisher = {Univ. J. E. Purkyn\v e - P\v r\'\i rodov\v edeck\'a fakulta},
     address = {Brno},
     year = {1973},
     pages = {261-267},
     mrnumber = {MR0349047},
     zbl = {0327.65078},
     url = {http://dml.mathdoc.fr/item/700073}
}

Whiteman, J. R.; Barnhill, R. E. Finite element methods for elliptic mixed boundary value problems containing singularities, dans Proceedings of Equadiff III, GDML_Books,  (1973), pp. 261-267. http://gdmltest.u-ga.fr/item/700073/