Scrum

Scrum Basics you need to know along with a vast range of subjects in form of questionnaire – http://agilescout.com/essential-scrummaster-interview-questions/

Spirit of Scrum – Scouts – Pragmatic, Value Based Servant Leaders – http://agilescout.com/agilescout/

Impediment Management in Scrum with a Visible Kanban Board – http://agiletrail.com/2011/09/05/7-steps-to-build-a-kanban-board-for-a-scrum-teams-impediments/

Scrum Reference Card, Michael James – http://scrumreferencecard.com/ScrumReferenceCard.pdf

Scrum Master Check list for Scrum Improvements, Michael James – http://blogs.collab.net/agile/a-scrummasters-checklist

The Formal Authority on Scrum and its processes – http://www.scrumguides.org/scrum-guide.html

How to Improve Agile / Scrum –  Review from Jeff Sutherland on 10th year of manifesto publication – https://msdn.microsoft.com/en-us/library/hh350860(v=vs.100).aspx