A cheat sheet for Set Theory. A basic understanding of Set Theory and its jargons (domains, ranges, functions) will be handy while reading most programming language theory-ish articles. Just understand Set Theory, Type Theory and the likes are just different ways of defining the same mathematical phenomenons.
The Turing Machine - Alan’s original paper explained for mortals
Algebraic data types (touches on recursive types)
An excellent resource for diving into Haskell. Abstracts away most math theory behind Haskell but you’ll get a hand of the language.
http://learnyouahaskell.com/recursion#hello-recursion Start with recursion, just for the fun of it!
Don’t let the title mislead you. I had an Aha moment on Lambda Calculus itself reading mid-way.
YCombinator - decrypted for mortals.
The science of functional programming (Haven’t finished reading yet, but looks very approachable)