Stefan–Boltzmann constant

https://doi.org/10.1351/goldbook.S05964
Fundamental physical constant \(\sigma = \frac{2\ \pi ^{5}\ k^{4}}{15\ h^{3}\ c_{0}^{2}} = 5.670\ 51(19)\times 10^{-8}\ \text{W}\ \text{m}^{-2}\ \text{K}^{-4}\).
Source:
CODATA Bull., 1986, 63, 1. [Terms] [Book]