What I need to know: The actual text of whatever statute covered the drinking age that year. I know 1984 was when the National Minimum Drinking Age Act passed, but according to Wikipedia Illinois had raised the state drinking age to 21 in 1980, and that's the law I really want the text of.
What I've tried: I've checked pretty much all the drinking-age related pages on Wikipedia, and googled "illinois drinking age" adding "statute," "law," "pre-1984," and "1980," "1981," and "1982." Most of the results were Wikipedia or pages about the modern debate over the drinking age. I finally found this page which gave me a summary of the bill and the bill number, so I tried googling "h.b. 21" adding various combinations of "illinois drinking age," "bill text," and "1979" to that search but still can't find the actual text.