Kellogg, D.O.; Baynes, T.S.; Smith, W.R. (1903). The Encyclopædia Britannica: New American supplement. A-ZUY. The Encyclopædia Britannica: A Dictionary of Arts, Sciences, and General Literature. Original 9th Ed. in 25 Vols. Werner. p. 673. Consultado el 24 de enero de 2015.
«Lamp». The Encyclopedia Americana16. Encyclopedia Americana Corp. 1919. p. 681.