APA

(1981). Tours and visits directory: a behind-the-scenes guide to factories, mines, business firms, government agencies, cultural, and educational institutions, and other facilities which receive visitors. Detroit: Gale Research Co.

Chicago

1981. Tours and visits directory: a behind-the-scenes guide to factories, mines, business firms, government agencies, cultural, and educational institutions, and other facilities which receive visitors. Detroit: Gale Research Co.

Harvard

(1981). Tours and visits directory: a behind-the-scenes guide to factories, mines, business firms, government agencies, cultural, and educational institutions, and other facilities which receive visitors. Detroit: Gale Research Co.

MLA

Tours and visits directory: a behind-the-scenes guide to factories, mines, business firms, government agencies, cultural, and educational institutions, and other facilities which receive visitors. Detroit: Gale Research Co. 1981.