References
David E Smith
with LeVeque, W.J. (1971). Numerals and numeral systems. In Encyclopaedia Britannica 16 (pp. 756-760). London: Encyclopaedia Britannica.
with Zuber, M.T. (2017). The transfer of earth-time to the planets. In E. Felicitas arias, L. Combrinck, P. Gabor, & C. Hohenkerk (Eds.). The science of time 2016 (pp. 319-328). Dordrecht: Springer.