Here is what the page “Is There Evidence For a Vast Multiverse?” contains. In 1987, Steven Weinberg wrote a cute little paper entitled “Anthropic Bound on the Cosmological Constant”. I say cute little paper because it feels minor in comparison to, say, electroweak unification theory that won him the Nobel Prize.
Weinberg was foundational in establishing the standard model of particle physics, and represented an enormous leap in understanding how this universe works. But his little 1987 paper, though more obscure This listing links straight to the original page, where the content is available in full.