@inbook{GrosseWentrupSBG2013,
  title = {A Review of Performance Variations in SMR-Based Brain–Computer Interfaces (BCIs)},
  booktitle = {Brain-Computer Interface Research},
  pages = {39-51},
  chapter = {4},
  series = {SpringerBriefs in Electrical and Computer Engineering},
  editors = {Guger, C., Allison, B. Z. and Edlinger, G.},
  publisher = {Springer},
  year = {2013},
  author = {Grosse-Wentrup, M. and Sch{\"o}lkopf, B.},
  doi = {10.1007/978-3-642-36083-1_5}
}