Smalltalk-80: The Language and Its Implementation Adele Goldberg and David Robson
The Java Virtual Machine Specification Lindholm Yellin Bracha Buckley
"Generating LR syntax error messages from examples", Jeffery, ACM TOPLAS Volume 24 Issue 5 Sep 2003.
The Hindley-Milner Algorithm in perl by Nikita Borisov
https://medium.com/@dhruvrajvanshi/type-inference-for-beginners-part-2-f39c33ca9513