This Addendum acknowledges a previously overlooked 1971 work by I.P. Bazarov which anticipates the thermodynamic argument recently presented by the author Phys. Scr. 100, 125206 (2025). I discuss the rarity of this reference and its absence from standard textbooks to ensure a complete historical record of the relationship between thermodynamic stability and the vanishing of specific heats.
Jose Maria Martin-Olalla (Mon,) studied this question.