Specifically "fletcher4":

* https://openzfs.github.io/openzfs-docs/man/master/7/zfsprops...

* https://openzfs.github.io/openzfs-docs/Basic%20Concepts/Data...

* https://en.wikipedia.org/wiki/Fletcher%27s_checksum

* https://people.freebsd.org/~asomers/fletcher.pdf

* https://www.intel.com/content/www/us/en/developer/articles/t...

Originally documented in the paper "An Arithmetic Checksum for Serial Transmissions" (referenced also in RFC 1146, in the context of TCP).