I did that and found a paper I would rank highly: Hoare’s “An axiomatic basis for computer programming”[1].
I clicked through and saw that it was included in their 25th anniversary issue and that particular issue seems like an excellent place to start.[2]
[1]: https://dl.acm.org/doi/10.1145/357980.358001
[2]: https://dl.acm.org/toc/cacm/1983/26/1