Fernandez, H. Y. (1974). Selected economic geography concepts for the elementary school. s.n.].
Chicago-referens (17:e uppl.)Fernandez, Helen Yulo. Selected Economic Geography Concepts for the Elementary School. [Quezon City: s.n.], 1974.
MLA-referens (9:e uppl.)Fernandez, Helen Yulo. Selected Economic Geography Concepts for the Elementary School. s.n.], 1974.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.