look at these, too:

http://www.press.umich.edu/pdf/9780472031887-appendixg.pdf

http://www.essayforum.com/resumes-letters-19/ambitious-hard-working-recommendation-letter-admission-phd-45396/

http://gsi.berkeley.edu/teachingguide/profession/recletter4.html

http://gradschool.about.com/od/askingforletters/qt/Letter2.htm

http://homes.cs.washington.edu/~mernst/advice/write-recommendation.html

Dear Milad,

In my opinion all of details should be written an a perfect recommendation letter, such as your scores and even your behavior. there is some samples in this site:

http://www.wikihow.com/Write-a-Letter-of-Recommendation

Thanks @Mehrdad

look at these, too:

http://www.press.umich.edu/pdf/9780472031887-appendixg.pdf

http://www.essayforum.com/resumes-letters-19/ambitious-hard-working-recommendation-letter-admission-phd-45396/

http://gsi.berkeley.edu/teachingguide/profession/recletter4.html

http://gradschool.about.com/od/askingforletters/qt/Letter2.htm

http://homes.cs.washington.edu/~mernst/advice/write-recommendation.html

A professor should write a recommendation letter which hews as closely as possible to the application instructions given by the agency requiring the recommendation. This means brevity, concision, and an order imposed by the student´s application form. The longer the recommendation, the weaker its impact. Concrete examples are always appreciated.