Beckers, Gabriel J. L. Abteilung Gahr, Seewiesen, Max Planck Institut für Ornithologie, Max Planck Society;
Beckers, G. J. L., Bolhuis, J. J., Okanoya, K., & Berwick, R. C. (2012). Birdsong neurolinguistics: Songbird context-free grammar claim is premature. NeuroReport, 23(3), 139-145. doi:10.1097/WNR.0b013e32834f1765.