Business English: A Practice Book by Rose Buhlig

3. Using abbreviations

_a._ Of the introduction. Write out the introduction in detail, both name and address. Abbreviating this part of the letter is highly discourteous. _b._ In the body of the letter; as, _Wrong_: The Co. sent a no. of large orders last year. _c._ Of the courteous close; as, _Wrong_: Yours etc. _Wrong_: Yours resp'y.