Hello there,<br/><br/>both sounds correct to me, but I am sure that one of them is wrong.<br/><br/>So, how do you say this?<br/><br/>Dear Sir or Madam,<br/><br/>I am writing you with refernce to....<br/><br/>or <br/><br/>I am writing to you with reference to....<br/><br/>Hope to here from somebody who knows it,<br/><br/>Rene from Germany/ the Netherlands