Localized states of acoustic waves in three-dimensional periodic composites with point defectsFugen Wu, Huilin Zhong, Shao Zhong, Zhengyou Liu and Youyan LiuEur. Phys. J. B, 34 3 (2003) 265-268DOI: https://doi.org/10.1140/epjb/e2003-00220-6