Wohlleben effect in small grains of Bi-based high-temperature superconductors: evidence for intrinsic nature of spontaneous currentsN. Knauf, J. Fischer, B. Roden, R. Borowski, B. Freitag, B. Büchner, H. Micklitz, A. Freimuth, V. Kataev and D. I. KhomskiiEurophys. Lett., 35 7 (1996) 541-546DOI: https://doi.org/10.1209/epl/i1996-00148-y