Whittington, Goodwin, and Murray (2004). Transformational Leadership, Goal Difficuty, and Task Design: Independent and Interactive Effects on Employee Outcomes. Leadership Quarterly. 15, 5, 593-606. (Available in the e-Reserves tab in this course guide.)
Day and Antonakis, The Nature of Leadership, Chapter 8
Heifetz & Linsky, Leadership on the Line, Chapter 6