The records of the U.S. District Courts for the Districts of Oklahoma are included among Record Group 21 at the:
National Archives at Fort Worth
501 West Felix Street
Fort Worth, Texas 76115-3405
A guide to the holdings of the regional archives is available at: https://www.archives.gov/fort-worth/holdings
A published description of the records is also available in the Guide to Federal Records in the National Archives of the United States, 1995 (http://www.archives.gov/research/guide-fed-records/index.html ) .
Kellough, William C. "Oklahoma: The Territorial and District Courts" in James K. Logan, ed. The Federal Courts in the Tenth Circuit: A History. Denver: U.S. Court of Appeals for the Tenth Circuit, 1992.
Kellough, William C. "Power and Politics of the Oklahoma Federal Court." The Chronicles of Oklahoma 65 (1987): 182-213.