Cohen, Stephen D. “Some Arithmetical Functions in Finite Fields”. Glasgow Mathematical Journal, vol. 11, no. 1, 1970, pp. 21-36, https://doi.org/10.1017/s001708950000080x.
Cohen, S. D. (1970). Some arithmetical functions in finite fields. Glasgow Mathematical Journal, 11(1), 21-36. https://doi.org/10.1017/s001708950000080x
Cohen SD. Some arithmetical functions in finite fields. Glasgow Mathematical Journal. 1970;11(1):21-36.