2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/85400It is pointed out that in Greiner's book, ``Quantum Mechanics --An Introduction,'' there is a confusion between the wavelength spectral function and the (angular) frequency spectral function in the derivation of the Wien's displacement law.4 pages, no figurePhysics Educationtext