While many sources have yet to be digitized, many treatises, dance manuals and other historic references and documentation are readily available on the internet:
The Library of Congress – Dance Manuals
Digital Public Library of America
California Digital Newspaper Collection
Papers Past – New Zealand Newspapers
Library of Congress – Chronicling of America
Library of Congress – Images
National Jukebox – Original Music Recordings through the Library of Congress
New York Public Library Digital Collections
British Library Image Collection
JScholarship – Johns Hopkins Libraries
Tulane University Digital Library
Mississipi University Digital Collection
Indiana University Sheet Music Library
University of North Carolina at Chapel Hill 19th Century American Sheet Music Library
University of California Libraries
University of Minnesota Media Archives
Classic Ragtime Piano – Collection of Ragtime piano sheet music
Moving Image Research Collections at the University of South Carolina
University of Oxford Libraries
A List of Anti-Dance Treatises
There are also a number of individuals and organizations dedicated to the study and recreation of vintage dances:
Richard Powers, Dance Historian and Instructor at Stanford University
Joan Walton, Lecturer and Instructor at San Jose State University and the College of San Mateo
Catherine Turocy, an expert in 17th and 18th Century period performance
Mass Historia, a site by Walter Nelson that examines dances of the jazz age
Capering and Kickery, a site by Susan DeGuardiola that analyzes sources from the 16th century through the 1960s
The New York Baroque Dance Company, Ms. Turocy’s performance group, based in New York, New York
The Academy of Danse Libre, a performance group based in Palo Alto, California
Watch Your Step, a performance group based in Boulder, Colorado
Commonwealth Vintage Dancers, a performance group based in Boston, Massachusetts
The Flying Cloud Dance Academy, a performance group based in Cincinnati, Ohio
Lexington Vintage Dance, a performance group based in Lexington, Kentucky
Dances Through Time, a performance group based in San Francisco, California
The San Diego Vintage Dance Society, dedicated to producing vintage dance events across the United States
I have encountered the following scholarly articles in my searches:
The Music of James Reese Europe for Vernon and Irene Castle – Dissertation by Ralph G. Barrett for University of South Carolina (2013)
The Texas Tommy, Its History, Controversies, and Influence on American Vernacular Dance – Dissertation by Rebecca Ruth Strickland (2006). Electronic Theses, Treatises and Dissertations. Paper 1538.
Fascinating Rhythms 