@book{PPN593233549, title = {Grundgesetze der Arithmetik Bd. 2}, series = {GDML\_Books}, publisher = {Pohle}, address = {Jena}, year = {1903}, language = {de}, url = {http://dml.mathdoc.fr/item/PPN593233549} }
Frege, Friedrich Ludwig Gottlob. Grundgesetze der Arithmetik Bd. 2. GDML_Books (1903), http://gdmltest.u-ga.fr/item/PPN593233549/