The orbital magnetic dipole moment of a particle with mass $m$ and charge $q$ can be shown to be related to the orbital angular momentum through the equation
$$\displaystyle \boldsymbol\mu_L=\frac{q}{2m}\bf{L}.$$
One of the quantum mechanics textbooks has instead the same equation but with the speed of light in the denominator,
$$\displaystyle \boldsymbol\mu_L=\frac{q}{2mc}\bf{L}.$$
The same book also defined the spin magnetic dipole moment for the electron with a $c$,
$$\displaystyle \boldsymbol\mu_S=-g\frac{e}{2m_ec}\bf{S},$$
where $g$ is the usual Lande factor (~2).
Is the speed of light appearing in those equations just a typo? (but it is not in the book errata)