Agile in a downturn: Big Visible Value or die.
Big Visible Value highlights how the investment in time and money for “agility” affects strategic outcomes.
Scrum
Official Scrum Guide Updated!
November 2017, the official Scrum Guide was updated. http://www.scrumguides.org/scrum-guide.html See the “Parents of Scrum” Jeff Sutherland and Ken Schwaber discuss the updates, with lots of interesting background and color commentary. https://www.scrum.org/resources/2017-scrum-guide-update-ken-schwaber-and-jeff-sutherland The short guide itself and this video (runs just short of an hour) is fine primary source material.