No one has really written a paper about the history of all this (I also mentioned this paper [1] in one of my other comments). But if you read the original ML paper [0] you'll see how they developed the language (notably by using ISWIM's syntax as a base). Note also that they are solving a problem with LISP (and dismissing Algol languages entirely) by building in strong types.

[0] http://www.sciencedirect.com/science/article/pii/00220000789...

[1] https://archive.alvb.in/msc/11_infomtpt/papers/the-next-700_...