@article{JRAM_1983__341_152527,
     author = {Gustaf Gripenberg},
     title = {On a nonlinear integral equation modelling an epidemic in an age-structured population.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {54--67},
     publisher = {mathdoc},
     volume = {341},
     year = {1983},
     zbl = {0514.92027},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1983__341_152527/}
}