1. 1) G. A. Studebaker, ``Placement of vibrator in bone-conduction testing,'' J. Speech Hear. Res., 5, 321-331 (1962).
2. 2) M. McBride, T. Letowski and P. Tran, ``Bone conduction reception: Head sensitivity mapping,'' Ergonomics, 51, 702-718 (2008).
3. 3) X. Qin, S. Otsuka and S. Nakagawa, ``Contribution of placement in bone-conducted transmission: Comparison between condyle and mastoid,'' Proc. EMBC 2018 (2018).
4. 4) S. Stenfelt, T. Wild, N. Hano and R. L. Goode, ``Factors contributing to bone conduction: The outer ear,'' J. Acoust. Soc. Am., 113, 902-913 (2003).
5. 5) M. A. Stone, A. M. Paul, P. Axon and B. C. J. Moore, ``A technique for estimating the occlusion effect for frequencies below 125 Hz,'' Ear. Hear., 35, 49-65 (2014).