In legal research, Shepar's Citations is the best-known citator, a list of all the authorities citing a particular case, statute, or other legal authority. The name derives from a legal service begun by Frank Shepard (1848-1900) in 1873, when Shepard began publishing these lists in a series of books indexed to different jurisdictions. Among lawyers in the United States, the verb Shepardizing refers to the process of consulting Shepard's (or another citator) to see if a case has been overturned, reaffirmed, questioned, or cited by later cases.