What to read after A Guide to the Project Management Body of Knowledge?

"The PMBOK® Guide--Sixth Edition--PMI's flagship publication has been updated to reflect the latest good practices in project management. New to the Sixth Edition, each knowledge area will contain a section entitled Approaches for Agile, Iterative and Adaptive Environments, describing how these practices integrate in project settings. It will also contain more emphasis on strategic and business knowledge--including discussion of project management business documents--and information on the PMI Talent TriangleTM and the essential skills for success in today's market. Agile Practice Guide--Agile Practice Guide has been developed as a resource to understand, evaluate, and use agile and hybrid agile approaches. This practice guide provides guidance on when, where, and how to apply agile approaches and provides practical tools for practitioners and organizations wanting to increase agility. This practice guide is aligned with other PMI standards, including A Guide to the Project Management Body of Knowledge (PMBOK® Guide)--Sixth Edition, and was developed as the result of collaboration between the Project Management Institute and the Agile Alliance."--Amazon.com.