New method for improving properties of SMA coil springs K. K. Jee, J. H. Han, Y. B. Kim, D. H. Lee and W. Y. Jang Eur. Phys. J. Special Topics, 158 (2008) 261-266 Published online: 01 May 2008 DOI: 10.1140/epjst/e2008-00685-y