These are the main ones you need to start with:
Brophy, William S L C SMITH SHOTGUNS North Hollywood, Beinfeld (1977).
Butler, D. THE AMERICAN SHOTGUN
McIntosh, Michael BEST GUNS Traverse City, MI Countrysport Press 1999. New York Winchester Press 1973.
McIntosh, Michael A.H. Fox "The Finest Gun in the World" Countrysport
O'Connor, Jack Shotgun Book Alfred A. Knopf 1965
Schwing, Ned. The Browning Superposed
Schwing, Ned. Winchesters Finest, The Model 21
Stadt, Ronald W. Winchester Shotguns & Shotshells Armory Pr.
Semmer, Charles G., Remington Double Shotguns
Snyder, W., The Ithaca Gun Company - from the Beginning 2nd Ed.
Wieland, Terry SPANISH BEST Countrysport 1994
Zutz, Don. THE DOUBLE SHOTGUN. New York, Winchester Press
The Parker Story
