English language
Published July 14, 2003 by Houghton Mifflin Harcourt Trade & Reference Publishers.
the Essential Introduction to the Enneagram, Revised and Expanded
Don Richard Riso, Russ Hudson: Discovering Your Personality Type (2003, Houghton Mifflin Harcourt Trade & Reference Publishers)
English language
Published July 14, 2003 by Houghton Mifflin Harcourt Trade & Reference Publishers.