Adams, Bruce and Engel, Peggy. Ballpark Vacations: Great Family Trips to Minor League and Classic Major League Baseball Parks Across America. Fodor's (a division of Random House), April 1997. ISBN 0-679-03152-9.
Chapter 17 covers trips to Northern League ballparks (St. Paul, Sioux City). [Web site]
Berg, Bruce (text) and Aligada, Reggie (photographs). Common Ground: McElroy Park's Jack Brown Stadium. Fargo, ND: Common Ground Press, 1996. ISBN 0-9653020-0-8.
A commemorative look back at the history of baseball in Jamestown, ND. Including reminiscences from those who played on (or knew those who played on) amateur, semi-pro, minor, and Negro league teams in the area. Contains (very) brief mention of the Northern League, pp. 5, 10, 12-13, and 19.
Brauer, David. No hits, no runs, one political error (St. Paul Saints President Mike Veeck). Corporate Report-Minnesota, 26(2), page 76, February 1995. (InfoTrac article A16641970)
Coste, Chris. Hey ... I'm Just the Catcher: An inside look at a Northern League season from behind the plate. Fargo, ND: Jan Plaude Creations, 1997. [R317]
Describes the 1996 Northern League season, by the Fargo-Moorhead RedHawks catcher.
Fatsis, Stefan. Wild and Outside: how a regegade minor league revived the spirit of baseball in America's heartland. New York: Walker Publishing, 1996.
Covers the formation of the Northern League and its first two seasons (1993, 1994). Some notes about 1995 season.
Humber, William. Diamonds of the North: A Concise History of Baseball in Canada. Ontario: Oxford University Press, 1995. ISBN 0-19-541039-4.
Appendix C contains some information about Northern League teams and pennant winners.
Johnson, Lloyd and Miles Wolff (editors). The Encyclopedia of Minor League Baseball (First Edition). Durham, NC: Baseball America, Inc., 1993. ISBN 0-9637189-1-6.
Lots of information about standings, playoffs, batting and pitching leaders.
Jordan, Pat. St. Paul's Zaniest Saints. Reader's Digest, 151(905), pp. 113-117, September, 1997. (Printed originally in Men's Journal, don't know what issue.)
Lidz, Franz and Christian Stone (editors). Veecking havoc. Sports Illustrated, 83(4), page 12, July 24, 1995.
Muret, Don. Winnipeg Goldeyes aim for another 200,000. Amusement Business, 108(9), p. 15, Feb 26, 1996. (InfoTrac article A18036720)
The Goldeyes aim for their third consecutive season of 200,000+ attendance. (As it turned out, season attendance was 171,351.)
O'Brien, Richard and Hank Hersch (editors). English lessons. Sports Illustrated, 87, p. 22, July 7, 1997.
Keith English of the Duluth-Superior Dukes is traded for Ila Borders of the St. Paul Saints.
O'Brien, Richard and Hank Hersch (editors). Breaking borders. Sports Illustrated, 86(24), page 24, June 16, 1997.
Perlstein, Steve. Rebel Baseball: The Summer the Game was Returned to the Fans. New York: Owl Books; reprint, Onion Press, 1994. ISBN 0-8050-3953-8.
Primarily covers the St. Paul Saints 1993 season.
Pietrusza, David. Minor Miracles: The Legend & Lure of Minor League Baseball. South Bend, IN: Diamond Communications, 1995. ISBN 0-912083-82-4.
Chapter 23 ("Declaration of Independence") discusses the Northern League: why it was started, who started it, other background information. Chapter 24 ("Strike Insurance") contains scattered Northern League-related remarks about minor and independent league baseball during the major league strike of 1994.
Richmond, Peter. Veeck II: Meet Mr. Minors. GQ - Gentleman's Quarterly, 65(4), page 211, April 1995.
Shipnuck, Alan. Northern Exposure. Sports Illustrated, 81(8), pp. 68-69, August 22, 1994.
Discusses Northern League baseball during the major league player's strike of 1994.
White, Herman D. An Informal History of the Northern Baseball League. Gryphon Press: St. Paul. 1982.
A short (20 pages) history by a man who was himself president of the Northern League from 1935-1957 and 1961-1962. [online version]
If you have other sources of Northern League reading, please let me know.