Acknowledgements

This bibliography has been compiled with the help of Lucas Antiqueira, Andrea Barochelli, Brita Elvevåg, Silvia Caldeira, Radek Čech, Joshua Gerrish, Yoed Kenett, László Kóvacs, Haitao Liu, Adolfo Paolo Masucci, Alexander Mehler, Anat Ninio, Stefano Nolfi, Morgan Sonderegger and Michael Vitevitch.