Most of the earlier surveys used a variety of complex schemes for naming and identifying sources. Unfortunately, the use of many names for a single source has led to needless confusion among workers. The recognition of this problem has led to the growing use of a system first used in the Parkes catalog. In this system each source is identified by a name of the form HHMM±DD, where HHMM represents the hours and minutes of right ascension, and ±DD the degrees of declination prefixed by the sign. In order to preserve the identity of the observatory, the catalog name is. frequently preceded by a symbol identifying the observatory. Some prefixes in common use are PKS (Parkes), DW (Dwingeloo), B (Bologna), G (Green Bank), A (Arecibo). Often additional symbols are used to identify a particular survey.