@ARTICLE{
author={Essa K,Kacmarcik Igor,Hartley P,Plancak Miroslav E,Vilotic Dragisa},
year={2012},
title={Upsetting of bi-metallic ring billets},
journal={JOURNAL OF MATERIALS PROCESSING TECHNOLOGY},
volume={212},
number={4},
pages={817-824},
document_type={Article},
}