Citazione Stile APA (7a Edizione)

Bolivar, J. D. (1987). A proposed syllabus and teaching material in economic geography for the secondary school. s.n.

Citazione stile Chigago Style (17a edizione)

Bolivar, Juliana D. A Proposed Syllabus and Teaching Material in Economic Geography for the Secondary School. s.l: s.n, 1987.

Citatione MLA (9a ed.)

Bolivar, Juliana D. A Proposed Syllabus and Teaching Material in Economic Geography for the Secondary School. s.n, 1987.