2003NEMA C78.21-2003 For Electric Lamps - PAR and R Shapes [Replaced: ANSI C78.21, ANSI C78.21, ANSI C78.21]
1995NEMA C78.21-1995 American National Standard for Incandescent Lamps - PAR and R Shapes (Includes: Supplement C78.21a-1996@ Supplement C78.21c-1998@ and Supplement C78.21b-1999)
1989NEMA C78.21-1989 ELECTRIC LAMPS - INCANDESCENT LAMPS - PAR AND R SHAPES