Chapter XII. Complex Numbers.
Algebra Part 1, GDML_Books, (1889), p. 221 / Harvested from
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@article{PPN585262896+DMDLOG_0016,
     title = {Chapter XII. Complex Numbers.},
     booktitle = {Algebra Part 1},
     series = {GDML\_Books},
     publisher = {Black},
     address = {Edinburgh},
     year = {1889},
     pages = {221},
     url = {http://dml.mathdoc.fr/item/PPN585262896+DMDLOG_0016}
}

 (éd.). Chapter XII. Complex Numbers., dans Algebra Part 1, GDML_Books,  (1889), p. 221. http://gdmltest.u-ga.fr/item/PPN585262896+DMDLOG_0016/