Howell, J. P., & Costley, D. L. (2006). Understanding behaviors for effective leadership (2nd ed.). Pearson/Prentice Hall.
Lua i Stíl Chicago (17ú heag.)Howell, Jon P., agus Dan L. Costley. Understanding Behaviors for Effective Leadership. 2nd ed. Upper Saddle River, N.J. ; New Delhi: Pearson/Prentice Hall, 2006.
Lua MLA (8ú heag.)Howell, Jon P., agus Dan L. Costley. Understanding Behaviors for Effective Leadership. 2nd ed. Pearson/Prentice Hall, 2006.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.