Шифрин, Б.М. “Friction on Air Wheels: An Applicability of Keldysh-Neymark-Fufaev Models”. Problems of Tribology 74, no. 4 (June 19, 2015): 96–101. Accessed October 12, 2023. https://tribology.khnu.km.ua/index.php/ProbTrib/article/view/414.