http://www.robotsquids.blogspot.ca/2013/09/sliding-pivot-foot-roll-tutorial.html
http://chrislesage.com/character-rigging/using-a-unit-vector-to-make-a-cylindrical-foot-roll/
http://alexwidener.github.io/ribbon-spine.html
http://hippydrome.com/Shldr.html
http://hippydrome.com/Legs.html
Lot's of great stuff on that channel ^
Some Topology reference:
https://sites.google.com/site/facaelectrica/topology-1/joints
Spine/Bone Placement:
http://www.lifelikeandbelievable.com/blog/backbone-animation/
Follicles:
http://www.nkoubi.com/blog/tutorial/the-animators-guide-to-follicles/
Correctives:
https://circecharacterworks.wordpress.com/2011/03/26/presentation/
https://circecharacterworks.wordpress.com/2011/07/06/a-journey-in-the-realm-of-corrective-shapes-ii/
Face Rigging:
https://circecharacterworks.wordpress.com/2011/10/25/facial-rigging-a-parametric-experiment/