@article{01883693, title = {Examples of Friedrichs model operators with a cluster point of eigenvalues.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {2003}, year = {2003}, pages = {625-638}, doi = {10.1155/S0161171203202155}, zbl = {1053.47014}, language = {en}, url = {http://dml.mathdoc.fr/item/01883693} }
Iakovlev, Serguei I. Examples of Friedrichs model operators with a cluster point of eigenvalues.. International Journal of Mathematics and Mathematical Sciences, Tome 2003 (2003) pp. 625-638. doi : 10.1155/S0161171203202155. http://gdmltest.u-ga.fr/item/01883693/