MUMPS (M) is a high performance transaction processing key–value database with integrated programming language.

M history
https://en.wikipedia.org/wiki/MUMPS

M syntax
https://en.wikipedia.org/wiki/MUMPS_syntax

M standard
http://71.174.62.16/Demo/AnnoStd

M language guide
https://www.cs.uni.edu/~okane/source/MUMPS-MDH/MumpsUsersGuide.pdf
https://www.cs.uni.edu/~okane/source/MUMPS-MDH/MumpsTutorial.pdf

M language forum
https://groups.google.com/g/comp.lang.mumps

M pocket guide
http://vistaexpertise.net/bookstore/1995-standard-mumps-pocket-guide/1995-standard-mumps-pocket-guide.pdf

M example code
https://github.com/programarivm/mumps-examples
http://71.174.62.16/Demo/AnnoStd?Frame=Main&Page=a100006

M books
https://www.amazon.com/Mumps-Programming-Language-Kevin-OKane-ebook/dp/B00MZIMA1M

M training
https://www.pioneerdatasys.com/site/train/m2s.html

M utilities
https://www.hardhats.org/tools/MUtilframe.html

M blogs
https://www.datasciencecentral.com/mumps-the-most-important-database-you-probably-never-heard-of
https://www.elys.com/blog/mumps-the-arcane-database-language-behind-our-electronic-medical-records

M: Vista Programming
https://www.hardhats.org/tools/vpe/vpe_db.html
http://www.vistapedia.net/index.php/MUMPS_Overview
http://www.vistapedia.net/index.php/Introduction_To_Programming_VistA_with_MUMPS
http://www.vistapedia.net/index.php/VistA_Database_Globals
http://www.vistapedia.net/index.php/Object_Oriented_Programming_with_M

Reference standard mumps (RSM)
https://gitlab.com/Reference-Standard-M/rsm

YottaDB
https://gitlab.com/YottaDB
https://yottadb.com/product/get-started/
https://docs.yottadb.com/ProgrammersGuide/devcycle.html#overview-of-the-program-development-cycle
https://yottadb.com/connect-microsoft-analytics-and-business-intelligence-tools-to-octo/