TY  - BOOK
AU  - Kelly, James M.
AU  - Sackman, Jerome L., coaut.
ED  - University of California. Earthquake Engineering Research C-enter
TI  - Conservatism in summation rules for closely spaced modes / -by James M. Kelly and Jerome L. Sackman
CY  - Berkeley, Calif. : University of California, College of Engineering
ER  -