an Entity references as follows:
Clement D. Child (1868 – 1933) was an American physicist and educator. He is noted particularly for "Child's law" (1911), which is an equation that describes the electric current that flows between the plates of a vacuum tube. Vacuum tubes were the main components in electronics from about 1905 to 1960, when transistors and integrated circuits mostly supplanted them. Child's Law is still a staple of textbooks treating charged particle motion in vacuum and in solids.