Cita APA (7th ed.)

(1968). National Electrical Code 1968: A USA Standard. National Fire Protection Association.

Cita Chicago (17th ed.)

National Electrical Code 1968: A USA Standard. Boston: National Fire Protection Association, 1968.

Cita MLA (9th ed.)

National Electrical Code 1968: A USA Standard. National Fire Protection Association, 1968.