1. The Revision of Rowland's System of Standard Wave-Lengths
2. Schwartzschild, K.Gesell, Wiss. Gottingen, Nachr. Math.Phys. Klasse; 1906; p 41; alsoBerliner Ber Math. Phys. Klasse; 1914; p 1183.
3. U.S. EPA.Global WarmingPotentials,http://www.epa.gov/globalwarming/emissions/national/gwp/html;Global WarmingGlossary,http://www.epa.gov/globalwarming/glossary.html;Climate,http://www.epa.gov/globalwarming/climate/index/html; U.S. Government Printing Office, Washington, DC, 2000.