@article{articlef17ed444,
title   = {On the wave equation with a magnetic potential},
author = {Cuccagna, Scipio and Schirmer, Pedro Paulo Serpa},
year = {2001},
doi = {10.1002/1097-0312(200102)54:2%3C135::AID-CPA1%3E3.0.CO;2-4},
journal   = {Communications on Pure and Applied Mathematics}
}