Metode penelitian - Saifuddin Azwar (Pustaka Pelajar, 1998)
Bhr/C.1 / ir,c.2,3/oen, c.4/ir,c.5/ast c.6/oen, c.7/ir,c.8/ast c.9/sn.c.10/stoc6, c.1-4, 6/stoc1,c.10