@article{JRAM_1969__235_150913,
     author = {Allen R. Freedman},
     title = {Some generalizations in additive number theory.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {1--19},
     year = {1969},
     volume = {235},
     zbl = {0211.38301},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1969__235_150913/}
}