Hardiness Institute: http://www.hardinessinstitute.com/
Wild Resiliency Blog: http://wildresiliencyblog.com/
Books:
Resilience At Work, Salvatore, Maddi & Deborah Khoshabba
Resilience: How to Navigate Life's Curves, Kathryn Britton
Assessments:
Resiliency Map: Essi Systems
Hardiness Assessment