APA

Schaefer R., . (1999). Sociology. A brief Introduction. Boston: McGraw-Hill.

Chicago

Schaefer R.T, . 1999. Sociology. A brief Introduction. Boston: McGraw-Hill.

Harvard

Schaefer R., . (1999). Sociology. A brief Introduction. Boston: McGraw-Hill.

MLA

Schaefer R.T, . Sociology. A brief Introduction. Boston: McGraw-Hill. 1999.