APA

U.S. Congress. Hearings [90-39], . (1968). Highway safety, design and operations. Freeway signing and related geometrics. Washington: U.S. Congress. Hearings [90-39].

Chicago

U.S. Congress. Hearings [90-39], . 1968. Highway safety, design and operations. Freeway signing and related geometrics. Washington: U.S. Congress. Hearings [90-39].

Harvard

U.S. Congress. Hearings [90-39], . (1968). Highway safety, design and operations. Freeway signing and related geometrics. Washington: U.S. Congress. Hearings [90-39].

MLA

U.S. Congress. Hearings [90-39], . Highway safety, design and operations. Freeway signing and related geometrics. Washington: U.S. Congress. Hearings [90-39]. 1968.