Nuclear-spin-related properties of the dual-frequency Doppler-free resonanceRemoveE. A. Tsygankov, K. M. Sabakar, D. S. Chuchelov, M. I. Vaskovskaya, V. V. Vassiliev, S. A. Zibrov, and V. L. VelichanskyPhys. Rev. A 113, 013120 (2026)