Engstrom, T. W. (1985). The fine art of friendship: Building and maintaining quality relationships. Thomas Nelson.
Chicago-referens (17:e uppl.)Engstrom, Ted W. The Fine Art of Friendship: Building and Maintaining Quality Relationships. Nashville: Thomas Nelson, 1985.
MLA-referens (9:e uppl.)Engstrom, Ted W. The Fine Art of Friendship: Building and Maintaining Quality Relationships. Thomas Nelson, 1985.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.