The dimensionless constant ccgs = 2.99792458×1010 is numerically equal to the magnitude of the speed of light when the latter is expressed in cm/s. /wiki/Speed_of_light
IEEE/ASTM SI 10-2002.
American National Standard for Use of the International System of Units (SI): The Modern Metric System.
New York: IEEE, 30 December 2002, Section 3.3.3.
A.E. Kennelly (1903) "Magnetic units and other subjects that might occupy attention at the next international electrical congress" 20th Annual Convention of the American Institute of Electrical Engineers, 1903 https://dokumen.tips/documents/magnetic-units-and-other-subjects-that-might-occupy-attention-at-the-next-international.html