Exploring the Trans-Neptunian Solar System (1998)
A scientific description of the asteroid group called Centaurs.

http://books.nap.edu/openbook.php?record_id=6080&page=27

Site named 'spaced out'
Interesting site with Chiron facts in middle of page.

http://www.spacedout-uk.com/solar_system/solar_info.asp?site_id=15

Chiron
This article refers to Chiron as a planetoid.

http://www.astrology.com/aboutastrology/interpreting/planets/chiron.htm