Base Ball: A Journal of the Early Game is edited by John Thorn, is published by McFarland, and appears twice a year. It includes scholarly research articles, about one-half of which relate to origins topics. For more information, including recent article listings, visit the journal's web page at McFarland.
"19C Baseball" Website – Eric Miklich’s site at http://www.19cbaseball.com has considerable material on the pre-professional era, including the evolution of playing rules from 1845 on, the early players, changes in the playing field, and more
Updates to A Game of Inches -- Peter Morris maintains a website that posts updates to the data in his book A Game of Inches. “The nature of a book of firsts,” he notes, “is that it is always a work in progress.” The site is http://www.petermorrisbooks.com/.
The Protoball Project’s Chronologies – Data on primary sources of evidence on early ballplaying is tabulated in several documented chronologies at http://retrosheet.org/Protoball/chron.htm. The master chronology comprises nearly 1000 citations up to 1862, and there are 16 specialized timelines (on rounders, college play, ballplaying in NYC before the Knickerbockers, etc). The site is hosted by Retrosheet.
Craig Waff’s "Games Tabulation" – The Protoball site also features tables of newspaper coverage of baseball to 1860 compiled by Craig Waff. Over 1500 games are listed from New York and 19 other areas. Go to http://retrosheet.org/Protoball/GamesTab.htm.
Protoball’s Glossary of Games – About 40 baseball-like games (that use bases, team play, batting, etc) are listed, plus over 60 others that have most, but not all, of these features. Go to http://retrosheet.org/Protoball/Glossary.htm.
The Baseball Index – SABR has built "The Baseball Index: the First Base of Baseball Research". It is free and is publicly accessible. A search for “origins” returns about 650 hits, each being a full bibliographic citation for a published source. "Rounders" turns up about 50 sources, and “Doubleday” nets seven. An Advanced Search feature allows searches to be performed by title, author, topic, and date.
Protoball Bibliography – Over 350 books and articles that touch on origins. A version listed in chronological order is also there. Protoball will consult its holdings for researchers upon request.
Pocol Press’ Booklist – A booklist on nineteenth century baseball that includes many essential works on origins.