Levelt, Willem J. M. Language Production Group Levelt, MPI for Psycholinguistics, Max Planck Society;
Friederici, A., & Levelt, W. J. M. (1987). Spatial description in microgravity: Aspects of cognitive adaptation. In P. R. Sahm, R. Jansen, & M. Keller (Eds.), Proceedings of the Norderney Symposium on Scientific Results of the German Spacelab Mission D1 (pp. 518-524). Köln, Germany: Wissenschaftliche Projektführung DI c/o DFVLR.