All scholarship applications require one reference letter that details the applicant's need for financial assistance. This letter should be written by a different author from your general application letter and must describe your need for financial support. Needless to say, your reference should be familiar with your financial need, which is generally not your dissertation adviser.
The reference letter must be addressed to the VSA Summer Schools Administrator and received by March 1st (or Jan 27th if applying early) via email to firstname.lastname@example.org or as a hard copy to:
VSA Summer Schools Administrator,
1636 Sansom Street,
Philadelphia, PA 19103-5404