Piezoelectric spectroscopic studies of Zn1-x-yBexMnymixed crystals J. Zakrzewski, M. Malinski, K. Strzałkowski, F. Firszt, S. Legowski and H. Meczynska Eur. Phys. J. Special Topics, 154 (2008) 381-385 Published online: 15 March 2008 DOI: 10.1140/epjst/e2008-00580-7