Viscosity of Liquid Helium below the λ-Point by Pyotr Leonidovich Kapitza (1938; original publication; inspected first-edition English collected-paper reprint 1965)

Original versions: Doklady Akademii Nauk SSSR 18,21 (1938); Nature 141,74 (1938); inspected reprint pp.505–507. Primary research article. Chapter in Collected Papers of P. L. Kapitza, Volume II: 1938–1964; chapter revisers credited separately from the collaboration.