Elwira Pisarska, Piotr Stachowiak, and Andrzej Jeźowski, Observation of relaxation of molecular spins in CH₄ and CD₄ crystals in thermal conductivity experiment: Classical Cryocrystals, Low Temp. Phys. 33, (2007) [Fiz. Nizk. Temp. 33, 768-771, (2007)] DOI: https://doi.org/10.1063/1.2755190.