@article{PPN585262896+DMDLOG_0017, title = {Chapter XIII. Ratio and Proportion.}, booktitle = {Algebra Part 1}, series = {GDML\_Books}, publisher = {Black}, address = {Edinburgh}, year = {1889}, pages = {255}, url = {http://dml.mathdoc.fr/item/PPN585262896+DMDLOG_0017} }
(éd.). Chapter XIII. Ratio and Proportion., dans Algebra Part 1, GDML_Books, (1889), p. 255. http://gdmltest.u-ga.fr/item/PPN585262896+DMDLOG_0017/