Sjoerd Nijland has written a nice series of blogposts about his road to PSMIII:
Definition of Scrum
https://medium.com/serious-scrum/definition-of-scrum-2d1f224256c
Empiricism: Transparency
https://medium.com/serious-scrum/empiricism-transparency-33adad8fbba2
Empiricism: Inspection, Part One
https://medium.com/serious-scrum/empiricism-inspection-part-one-cc4cd8bf98a8
Empiricism: Inspection, Part Two
https://medium.com/serious-scrum/empiricism-inspection-part-two-fafb785bd0c0
Empiricism: Adaptation
https://medium.com/serious-scrum/empiricism-adaptation-975f044a09b2
Scrum Values
https://medium.com/serious-scrum/scrum-values-1203813e0220
The Scrum Team
https://medium.com/serious-scrum/the-scrum-team-75b8004a4bc2
The Scrum Master
https://medium.com/serious-scrum/the-scrum-master-729e223f4b64
The Scrum Master’s responsibilities
https://medium.com/serious-scrum/the-scrum-masters-responsibilities-7ee05cae707e
The Product Owner
https://medium.com/serious-scrum/the-product-owner-6b7a63fef8fe
The Development Team
https://medium.com/serious-scrum/the-development-team-575d69054a9b
The Sprint
https://medium.com/serious-scrum/the-sprint-40d0ccc895f9
Sprint Cancellation
https://medium.com/serious-scrum/sprint-cancellation-c9a9c66e8c99
Scrum’s Artifacts
https://medium.com/serious-scrum/scrums-artifacts-6f07abfab11
The Product Backlog
https://medium.com/serious-scrum/the-product-backlog-7aec7daf844f
Estimation
https://medium.com/serious-scrum/estimation-103de626551e