The following is a paper by H. Aspden published in Lettere al Nuovo Cimento, v. 33, pp. 481-484 (1982).
Abstract: The resonant-cavity model by which the author has recently explained the anomalous electron g-factor has an alternative resonant mode suited to a less stable particle. When this is analysed it is found to give a result in full accord with the g-factor of the muon.