1. *See the next section for more details regarding the general picture of flow at small Knudsen numbers.
2. † See, for example, the discussion of this question in the monographs: G. N. Patterson, “Molecular Flow of Gases,” Wiley, New York, 1956;
3. M. F. Shirokov, “Physical Basis of Gas Dynamics,” Fizmatgiz, 1958;
4. V. P. Shidlovskii, “Introduction to the Dynamics of Rarefied Gases,” Nauka Press, 1965.
5. *This problem apparently was first correctly formulated by Welander [P. Welander, Arkiv Fysik 7(6): 507 (1954)].