@article{article80e64439,
title   = {Topology optimized design of functionally graded piezoelectric ultrasonic transducers},
author = {Montealegre Rubio, Wilfredo and Buiochi, Flávio and Adamowski, Júlio Cezar and Silva, Emílio Carlos Nelli},
year = {2010},
doi = {10.1016/j.phpro.2010.01.114},
journal   = {Physics Procedia}
}