APA (7th ed.) Citation

London Transport Board & Penrose, D. (1970). London buses, map & list of routes: Specially folded for easy reference. London Transport.

Chicago Style (17th ed.) Citation

London Transport Board and David Penrose. London Buses, Map & List of Routes: Specially Folded for Easy Reference. [London]: London Transport, 1970.

MLA (9th ed.) Citation

London Transport Board and David Penrose. London Buses, Map & List of Routes: Specially Folded for Easy Reference. London Transport, 1970.