Investigating fold in OCaml: https://www.matt- mcdonnell.com/code/code_ocaml/ocaml_fold/ocaml_fold.html Free Introduction to OCaml Online Class: https://www.fun- mooc.fr/courses/parisdiderot/56002S02/session02/about https://metacpan.org/pod/List::Util#reduce All You Need is Fold (Midwest.io 2015): https://www.youtube.com/watch?v=bzHKp6p-Rlk