References:
While preparing this response I relied on my general knowledge of doping, personal files, specific publications and the following articles: 

1) Roberts S and Epstein D.  The Case Against Lance Armstrong.  Sports Illustrated.  January 2011.

2)  Catlin DH, Murray TH.  Performance Enhancing Drugs, Fair Competition, and Olympic Sport.  J American Medical Association 1996;276:231-237. (describes doping control and the system)

3)  Catlin DH, Hatton CK, Starcevic S.  Issues in detecting xenobiotic anabolic steroids and testosterone by analysis of athletes’ urine. Clinical Chemistry 1997;43:1280-1288. http://www.clinchem.org/cgi/reprint/43/7/1280.  (explains the TE ratio in detail)

4)  Catlin DH, Cowan DA, de la Torre R, Donike M, Fraisse D, Oftebro H, Hatton CK, Starcevic B, de la Torre X, Norli H, Geyer H, Walker CJ.  Urinary testosterone (T) to epitestosterone (E) ratios by GC/MS.  I.  Initial comparison of uncorrected T/E in six international laboratories.   J Mass Spectrometry 1996;31:397-402.  (measurement of the TE ratio)

5)  Essay dedication: Coleman DL and Coleman, JE.  The Problem of Doping.  Duke University School of Law.  Duke Law Journal, 2008.

6) Anonymous, Current Biography®, March 2010 issue, 2010. The H.W. Wilson Company (www.hwwilson.com).  (Catlin’s career)