1. Aoyama, Y., Inoue, Y., Hashimoto, W., & Ohsuga, M. (2005). Development and Assessment of a healing system “The Mind Wave” mediated by respiration. Japanese Journal of Biofeedback Research, 31, 27–34.
2. Durckheim, K.G. (2003). HARA. Die Erdmitte des Menschen (Y. Shitahodo, R. Ochiai, Y. Okuno, & T. Ishimura, Trans). HARA-Ningen no Jushin [Abdomen, Center of gravity in Human]. Chiba, Japan: Reitaku University Press.
3. Fumoto, M., Sato-Suzuki, I., Seki, Y., Mohri, Y., & Arita, H. (2004). Appearance of high-frequency alpha band with disappearance of low-frequency alpha band in EEG is produced during voluntary abdominal breathing in an eyes-closed condition. Neuroscience Research, 50(3), 307–317. https://doi.org/10.1016/j.neures.2004.08.005
4. Hakuin, E. (1757/1934). Yasen Kanna [Idle talk on a night boat], part 1. In Hakuin Osho Zenshu editing committee (Eds.), Hakuin Osho Zenshu [Complete Works of Priest Hakuin], Vol., 5 (pp. 349–366). Tokyo, Japan: Ryuginsha.
5. Hirata, A. (1811/1977). Shizuno Iwaya [The name of a place in Japan], part 2. In Hirata Atsutane Zenshu editing committee (Eds.), Hirata Atsutane Zenshu [Complete Works of Hirata Atsutane], Vol., 14 (pp. 471–506). Tokyo, Japan: Meityo Shuppan.