Roles / Pros and Cons / Examples / Video

https://study.com/academy/lesson/management-roles-and-principles.html
https://www.mindtools.com/pages/article/management-roles.htm
http://management.atwork-network.com/2008/04/15/mintzberg%E2%80%99s-10-managerial-roles/
http://www.youtube.com/watch?v=_NRWtd_SiU8 

Management Guru / Site / Thinkers / On Twitter

https://en.wikipedia.org/wiki/Business_guru
http://www.derekstockley.com.au/guru.html
http://www.thinkers50.com/
http://www.phdinmanagement.org/top-50-management-gurus-worth-following-on-twitter.html

Skills / Slides / Pros and Cons

http://www.articlesbase.com/management-articles/managerial-skills-708033.html
http://www.slideshare.net/melgazar/management-skills-3042878
http://www.rasmussen.edu/degrees/business/blog/different-management-styles/

Management styles / Details / Country / Change

https://en.wikipedia.org/wiki/Management_style
http://tutor2u.net/business/gcse/people_management_styles.htm
https://www.crossculture.com/uncategorized/6-leadership-styles-around-the-world-to-build-effective-multinational-teams/
http://www.inc.com/guides/201105/how-to-change-your-management-style_pagen_2.html