Magnetic field penetration in MgB2 single crystals: pinning and Meissner holes - V. Chabanenko; E. Kuchuk; V. V. Yurchenko; P. Mikheenko; I. Abalosheva; R. Cortйs-Maldonado; F. Pйrez-Rodrнguez; J. Karpinski; N. D. Zhigadlo; S. Katrych; R. Puźniak (Low Temperature Physics, 2014)