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It was before the Internet, so you're going to have to resort to more traditional research. You might have to go to the public library. The research librarian is going to need a date. JPII Madison Square Garden 1979 could be a start, but keep in mind the other things, like the setting you could see, the introduction, the age group of the audience, the layout of the stage, because there might have been two or more sessions, on more than one day, that year.
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