Sunohara, N; Tomi, H; Satoyoshi, E; Tachibana, S (Oct 1985). "Glabella tap sign. Is it due to a lack of R2-habituation?". Journal of the Neurological Sciences. 70 (3): 257–67. doi:10.1016/0022-510x(85)90167-4. PMID4056821.
Sunohara, N; Tomi, H; Satoyoshi, E; Tachibana, S (Oct 1985). "Glabella tap sign. Is it due to a lack of R2-habituation?". Journal of the Neurological Sciences. 70 (3): 257–67. doi:10.1016/0022-510x(85)90167-4. PMID4056821.