^Adler, Washington P-adic L functions and higher dimensional magic cubes, Journal of Number Theory, vol. 52, 1995, p.179. See also Adler, Mathematical Intelligencer. 1992
^Class numbers and extensions, Mathematische Annalen, vol. 214, 1975, p. 177
^Ferrero, Washington The Iwasawa invariant μp vanishes for abelian number fields, Annals of Mathematics, vol. 109, 1979, pp. 377–395. Another proof was provided by W. Sinnott, Inventiones Mathematicae, vol. 75, 1984, 273.