Before revision: Recommendation letters, while bearing some similarities, distinguish themselves from conventional references by virtue of the fact that the former are typically conveyed in a formal written format, whereas the latter tend to be shared informally through spoken communication via email or URL
After revision: Recommendation letters, while bearing some similarities, distinguish themselves from conventional references by virtue of the fact that the former are typically conveyed in a formal written format, whereas the latter tend to be shared informally through spoken communication via email or telephone.