MacTutor History of Mathematics: Xenocrates of Chalcedon  
   Biography, bibliography and list of related topics.
   http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Xenocrates.html

Columbia Encyclopedia: Xenocrates  
   Concise paragraph on this early scholarch.
   http://www.bartleby.com/65/xe/Xenocrat.html

Biography.com: Xenocrates  
   Concise paragraph on his teachings.
   http://search.biography.com/print_record.pl?id=11817

FOLDOC: Xenocrates  
   Entry from the philosophical database, with links to related entries.
   http://www.swif.uniba.it/lei/foldop/foldoc.cgi?Xenocrates

Xenocrates  
   A detailed article by Russell Dancy on this thinker's life and teachings. From the Stanford Encyclopedia of Philosophy.
   http://plato.stanford.edu/entries/xenocrates/

Ancient Greek Scientists: Xenocrates of Chalcedon  
   Notes on his life and mathematical achievements.
   http://www.tmth.edu.gr/en/aet/1/98.html

Wikipedia: Xenocrates  
   Entry drawn from the 1911 Britannica.
   http://www.wikipedia.org/wiki/Xenocrates

Life of Xenocrates  
   Section from the Lives of the Philosophers, as compiled by Diogenes Laertius and translated by C.D. Yonge.
   http://classicpersuasion.org/pw/diogenes/dlxenocrates.htm