And I quote:
"We require either one composite/committee evaluation from your school OR three individual letters of recommendation. The individual letters must be submitted by professors under whom you have studied, persons who have supervised your work experience(s) or others who are uniquely qualified to comment on your potential for the study of medicine.
Submission Procedures:
1. Letters must come directly from the school or individual authors with your full name and social security number or AMCAS ID number included.
2. Letters must be on Letterhead Stationary and include the author's title and telephone number.
3. Authors of individual letters must sign the back flap of the business envelope (if not sent in an official letterhead envelope), with their signature intact upon arrival to the Admissions Office."
Then some mumbo jumbo about how if you dont adhere to these policies they will saw your arm off...
Hope this helps.