V.L. Gurtovoi, A.I. Ilin, A.V. Nikulov, and V.A. Tulin, Weak dissipation does not result in disappearance of persistent current, Low Temp. Phys. 36, (2010) [Fiz. Nizk. Temp. 36, 1209-1218, (2010)] DOI: https://doi.org/10.1063/1.3518606.