APA

Babbie E. R., Earl R. Babbie, .The practice of social research. Belmont: .

Chicago

Babbie Earl R, Earl R. Babbie, .The practice of social research. Belmont: .

Harvard

Babbie E. R., Earl R. Babbie, .The practice of social research. Belmont: .

MLA

Babbie Earl R, Earl R. Babbie, .Belmont: . .