Christie, L. (1987). Unsung heroes: How to recruit and train volunteer youth workers. Zondervan.
Cita Chicago (17th ed.)Christie, Les. Unsung Heroes: How to Recruit and Train Volunteer Youth Workers. Grand Rapids: Zondervan, 1987.
Cita MLA (9th ed.)Christie, Les. Unsung Heroes: How to Recruit and Train Volunteer Youth Workers. Zondervan, 1987.
Atenció: Aquestes cites poden no estar 100% correctes.