APA

(1991). Types of Maps. Reston, VA: U.S Dept. of the Interior, U.S. Geological Survey.

Chicago

1991. Types of Maps. Reston, VA: U.S Dept. of the Interior, U.S. Geological Survey.

Harvard

(1991). Types of Maps. Reston, VA: U.S Dept. of the Interior, U.S. Geological Survey.

MLA

Types of Maps. Reston, VA: U.S Dept. of the Interior, U.S. Geological Survey. 1991.