These are words that almost always sounds bad in college writing, usually because no one really talks that way. Sometimes they are also ungrammatical or the result of a failed attempt to sound more intellectual. Other times they are misguided attempts to avoid repetition. Occasionally below I suggest the word you should use instead. Notice how it's almost always a simpler word.
Exhibits that (ungrammatical and slightly pretentious. Use "shows" instead)
Expresses that (ungrammatical and very inelegant. Use "argues" or "says" instead)
Aforementioned (archaic and pretentious. Only use this satyrically)
Some words or phrases are just inherently weak. Here are some examples:
Refers to (I don't say you should never use it, but especially if you have a person as the subject of the sentence, a verb like "contends" or "argues" is always going to be stronger and have more forward motion)