•
Tombstone A.T. : business section, May 1882, by Robert N. Mullin, 1950 •
New Light on the Legend of Billy the Kid, New Mexico Folklore Record, 6 (1953), 1-5.
Philip J. Rasch and Robert N. Mullin. •
Dim Trails: The Pursuit of the McCarty Family, New Mexico Folklore Record, 8 (1954), 6-11. Philip J. Rasch and Robert N. Mullin. •
A Chronology of the Lincoln County War : scene: Mostly Lincoln County, New Mexico, time: mainly 1877-1881, by Robert N. Mullin, 1966 •
The Boyhood of Billy the Kid, by Robert N. Mullin, 1967 •
The Key to the Mystery of Pat Garrett, by Robert N. Mullin, 1969 •
The Strange Story of Wayne Brazel, by Robert N. Mullin, 1970 •
An Item from old Mesilla, by Robert N. Mullin, 1971 •
Tombstone, Arizona Territory, circa 1881-82, by Robert N. Mullin, 1971 •
Stagecoach Pioneers of the Southwest, by Robert N. Mullin, 1983 ==References==