@article{PPN236020595+dmdlog240, title = {OLBERS an BESSEL, 1820 April 20}, booktitle = {Nachtraege zur Physik, Chronologie und Astronomie Bd.11, Abt.1}, series = {GDML\_Books}, year = {1927}, pages = {319}, url = {http://dml.mathdoc.fr/item/PPN236020595+dmdlog240} }
(éd.). OLBERS an BESSEL, 1820 April 20, dans Nachtraege zur Physik, Chronologie und Astronomie Bd.11, Abt.1, GDML_Books, (1927), p. 319. http://gdmltest.u-ga.fr/item/PPN236020595+dmdlog240/