The Edison National Historical Park archives has seven bound volumes and one pamphlet of Patent Office proceedings relating to conflicting claims over who invented the telephone. Four of these volumes contain the record of a group of interferences entitled Cases A through L and Case No. 1. The disputant parties were Thomas Edison, Alexander Graham Bell, Elisha Gray, A. E. Dolbear, J. W. McDonough, George B. Richmond, William L. Voelker, J. H. Irwin, and Francis Blake, Jr. Although Edison's preliminary statements were filed in September 1878, testimony was not taken until 1880. This record was printed in 1881.
The first volume contains Edison's preliminary statements and the depositions of Edison and his witnesses. This volume has been selected in its entirety. Courtesy of Thomas Edison National Historical Park.