D´Ooge, Martin L., tr. <br/><br/>
Introduction to arithemetic : nicomachus of gerasa 

 - PP. 811-847 
<br/><br/> En: Euclid archimedes apollonius of perga nicomachus, tomo 11 / ed. Robert Maynard Hutchins. Chicago : Enciclopedia Britanica Inc., 1987