https://guides.bear-lab.com/Guide/Extrusion+multiplier+and+filament+diameter/8?lang=en
Tutorial on how to define flow rate and print speed range for your filament.
https://www.proto-pasta.com/blogs/how-to/leveling-up-your-printer-game-on-the-lulzbot-mini
https://www.sublimelayers.com/2016/10/some-musings-on-retracts.html
https://github.com/prusa3d/Prusa-Firmware/wiki/Extruder-linearity-correction-calibration