Test Maturity Model integration (TMMi® Model) is a freely available software quality and test maturity model . This model has been verified as the number one model for testing process improvement in the world.
There are information certification programs called TMMi Professional and TMMi test process developer to demonstrate understanding of the model and provide visibility for leading professionals in testing process improvement.
You can access the resources prepared by TMMi here. Resources are regularly updated by TMMi.
You can access the "TMMi®️ in an Agile World" document prepared by TMMi®️ and published in Turkish by TTB®️ here.
Turkish Testing Board continues working as the TMMi® Turkey local chapter.