Online References and Informational Sources
The New Grove Dictionary of Music and Musicians, Second Edition, Online
Likely the most comprehensive, reliable, authoritative and most frequently cited encyclopedia of music on the planet. While the price of an individual subscription seems prohibitive, you may already have free and easy access through various institutions such as your public library or a school with which you are affiliated.
Books
Chamber Music, by Homer Ulrich, Columbia University Press, New York and London, 1948, 1966
Chamber Music, by Alec Robertson, Penguin Books, Baltimore Maryland, 1957
Chamber Music: A Research and Information Guide, by John H. Baron, Routledge, New York, NY, 2003
Cobbett's Cyclopedic Survey of Chamber Music: Volumes I-III, by Walter Willson Cobbett, Oxford University Press, Amen House, London, 1963
Early Chamber Music, by Ruth Halle Rowen, Da Capo Press, New York, 1949, 1974
English Chamber Music: The History of a Great Art From the Middle Ages to Purcell, by Ernst H. Meyer, Lawrence and Wishard, London, 1936
Guide to Chamber Music: A Listener's Guide, by Melvin Berger, Anchor, Doubleday, New York, NY, 1985, 1990
Guide to Sonatas: Music for One or Two Instruments, by Melvin Berger, Anchor, Doubleday, New York, NY, 1991
Harvard Dictionary of Music, Second Edition, by Willi Apel, The Belknap Press of Harvard University Press, Cambridge, Massac, 1972
Johann Sebastian Bach's Chamber Music: Background, Analyses, Individual Works, by Hans Vogt, Amadeus Press, Portland, Oregon, 1981, 1988
Nineteenth-Century Chamber Music, by Stephen E. Hefling, Routledge, New York, NY, 1998
The Art of String Quartet Playing: Practice, Technique and Interpretation, by M. D. Herter Norton, W. W. Norton and Company, New York, NY, 1962, 1962
The Beethoven Quartets, by Joesph Kerman, W. W. Norton and Company, New York, London, 1966
The Chamber Music of Brahms, by Daniel Gregory Mason, The Macmillan Company, New York, 1933
The Chamber Music of Brahms, by Henry Sandwith Drinker, Jr., Greenwood Press, Publishers, Wesport, Connecticut, 1930
The Four and the One. In praise of String Quartets, by David Rounds, Lost Coast Press, Fort Bragg, CA, 1999
The Ill Tempered String Quartet: A Vademecum for the Amateur Musician, by Lester Chafetz, McFarland and Company, Inc., Publishers, Jefferson, NC, 1989
The Italian 'Trio' Sonata: Froms its Origins Until Corelli, by Peter Allsop, Clarendon Press, Oxford, 1992
The Literature of Chamber Music: Volume I-IV, by Arthur Cohn, Hinshaw Music Inc., Chapel Hill, NC, 1997
The New Grove Dictionary of Music and Musicians, Second Edition, Online, by , Oxford University Press, 2001
The Sonata in the Baroque Era, by William S. Newman, W. W. Norton and Company, Inc., New York, 1959, 1972
The Sonata in the Classic Era, by William S. Newman, W. W. Norton and Company, Inc., New York, 1963, 1972
The String Quartet: A HIstory, by Paul Griffiths, Thames and Hundon Inc., New York, 1983
The Trio Sonata, by Christopher Hogwood, BBC Publications, 1979
The Viola da Gamba: Its Origin and History, Its Technique and Musical Resources, by Nathalie Dolmetsch, Hinrichsen Edition, Ltd., London, 1962
Twentieth-Century Chamber Music, by James McCalla, Routledge, New York, NY, 1996
Violin and Keyboard: The Duo Repertoire: Volume 1 and 2, by Abram Loft, Grossman Publishers, New York, 1973