@inproceedings{inproceedings2d099d3a,
title   = {Multiple scales analysis of nonlinear oscillations of a portal frame foundation for several machines},
author = {Brasil, Reyolando Manoel Lopes Rebello da Fonseca},
year = {1997},
publisher = {Abcm},
booktitle   = {International Conference on Dynamic Problems in Mechanics}
}