@article{albarran2010comparison,
  title={A comparison of the scientific performance of the U.S. and the European Union at the turn of the 21st century},
  author={Albarran, Pedro and Crespo, Juan A. and Ortuno, Ignacio and Ruiz-Castillo, Javier},
  journal={Scientometrics},
  year={2010},
  volume={85},
  number={1},
  pages={329--344},
  doi={10.1007/s11192-010-0223-7}
}