APA (7th ed.) Citation

I.M. Imprimit (Firm), Johnston, E., & Mortimer, I. (1993). Johnston Sans: Trial proofs (Archive set B-E.). London Transport Museum.

Chicago Style (17th ed.) Citation

I.M. Imprimit (Firm), Edward Johnston, and Ian Mortimer. Johnston Sans: Trial Proofs. Archive set B-E. London: London Transport Museum, 1993.

MLA (9th ed.) Citation

I.M. Imprimit (Firm), et al. Johnston Sans: Trial Proofs. Archive set B-E. London Transport Museum, 1993.