  We review the exact solutions of several transcendental equations, obtained
by Siewert and his co-workers, in the '70s. Some of them are expressed in terms
of the generalized Lambert functions, recently studied by Mez\"o, Baricz and
Mugnaini. For some others, precise analytical approximations are obtained. In
two cases, the asymptotic form of Siewert's solutions are written as Wright
omega functions.
