I'm referring to the post "refer the letter x refer to the letter"
The tags are of the vaguest kind: grammar word-usage sentence-construction phrase-usage. I suggest to remove all these vague tags and replace them with verb-construction. The problem here is not grammar (a very large area). Word-usage is vague as we have a lot of word classes. The poster does not ask about the structure of the sentence, he does not know how the verb to refer can be constructed: to refer sth to sb or to refer to sth.