It's subject. There are four steps to a memo, the first step is the person it's going to, the second is from the person that sent it, the third step is the date it was sent, and finally the last step is what the memo is about, which is the subject.
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If this is what you are looking for, it would be nice if you could give me five stars, and a thanks.
Write her resources on a piece of paper and number them. Whenever you write down a fact write down the corespondent number of where you got it from right next to it.