  An English (2024) translation by P. Marquet of 3 German papers about "Die
Quantenhypothese f\"ur Molekeln mit mehreren Freiheitsgraden (The quantum
hypothesis for molecules with multiple degrees of freedom)" and "Bemerkung
\"uber die Entropiekonstante zweiatomiger Gase (Remarks on the entropy constant
of diatomic gases)" by Max Planck (1915,a,b,c)
