@article{JRAM_1980__314_152214,
     author = {Werner-Georg Nowak},
     title = {A non-convex generalization of the circle problem.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {136--145},
     publisher = {mathdoc},
     volume = {314},
     year = {1980},
     zbl = {0417.10042},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1980__314_152214/}
}