Here's the Milner paper which describes ML's type system. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.67.5276&rep=rep1&type=pdf http://citeseerx.is

Here's the Milner paper which describes ML's type system. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.67.5276&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.67.... Wikipedia also helps: https://en.wikipedia.org/wiki/Type_rules https://en.wikipedia.org/wiki/Type_rules