. . "Opinion of Thomas Ewing : on the validity of the claims of the American Bell Telephone co., under the patent, to A.G. Bell, of March 7, 1876"@en . . "Opinion of Thomas Ewing on the validity of the claims of the American Bell Telephone Co., under the patent, to A.G. Bell, of March 7, 1876"@en . . . . . . . . . . . "Opinion of Thomas Ewing : on the validity of the claims of the American Bell Telephone Co., under the patent, to A.G. Bell, of March 7, 1876" . . . . .