Hahah, looking up all the resources recommended here, I came across my original PADI book, which I still have. Yep, I was certified in 1988
https://www.amazon.com/PADI-Open-Water-Diver-Manual/dp/B000KFYGQE/ref=sr\_1\_13?keywords=scuba+diving+manual&qid=1639461379&sr=8-13