APA
Open University Cource Team, . (1973). History and institutions, unit. 1&2. GB: Open University Press.
Chicago
Open University Cource Team, . 1973. History and institutions, unit. 1&2. GB: Open University Press.
Harvard
Open University Cource Team, . (1973). History and institutions, unit. 1&2. GB: Open University Press.
MLA
Open University Cource Team, . History and institutions, unit. 1&2. GB: Open University Press. 1973.
