APA

U.S. Congress. Hearings [90-21], . (1968). Highway safety, design and operations. Roadside hazards. Washhington: U.S. Congress. Hearings [90-21].

Chicago

U.S. Congress. Hearings [90-21], . 1968. Highway safety, design and operations. Roadside hazards. Washhington: U.S. Congress. Hearings [90-21].

Harvard

U.S. Congress. Hearings [90-21], . (1968). Highway safety, design and operations. Roadside hazards. Washhington: U.S. Congress. Hearings [90-21].

MLA

U.S. Congress. Hearings [90-21], . Highway safety, design and operations. Roadside hazards. Washhington: U.S. Congress. Hearings [90-21]. 1968.