APA (7th ed.) Citation
Billings, R. R., Laurence, M., & Shelton, W. ". México: Postal issue of 1874-1883 (Hidalgo Heads).
Chicago Style (17th ed.) Citation
Billings, R. R., Michael Laurence, and W.E. "Bill" Shelton. México: Postal Issue of 1874-1883 (Hidalgo Heads).
MLA (9th ed.) Citation
Billings, R. R., et al. México: Postal Issue of 1874-1883 (Hidalgo Heads).
Warning: These citations may not always be 100% accurate.