@patent{blau_implantable_2009,
 author = {Blau, M. and Bornitz, M. and Zahnert, T. and Hofmann, G. and Hüttenbrink, K. B.},
 title = {Implantable converter for cochlea implants and implantable hearing aids},
 year = {2009},
 number = {US Patent 7,481,761},
}