1. [CIE] Commission Internationale de l’Eclairage. 1948. Compte Rendu. CIE 11th Session. Paris (France). p. 5.
2. [CIE] Commission Internationale de l’Eclairage. 1965. Method of measuring and specifying colour rendering properties of light sources. Paris (France): CIE. Publication No. CIE 13-1965. 34 p.