Gaya APA

Langbein, L, I. (1980). Discovering whether programs work : a guide to statistical methods for program evaluation / Laura Irwin Langbein (Cet.1). : Goodyear Publishing Company.

Gaya MLA

Langbein, Laura, Irwin. "Discovering whether programs work : a guide to statistical methods for program evaluation / Laura Irwin Langbein". Cet.1 : Goodyear Publishing Company, 1980. Textbook.