Igaki, M., Suzuki, M., Sakamoto, I., Ichiba, T., Kuriyama, K., & Uchiyama, M. Effects of bedtime periocular and posterior cervical cutaneous warming on sleep status in adult male subjects: a preliminary study. Sleep and Biological Rhythms, 16(1), 77-84. https://doi.org/10.1007/s41105-017-0129-3 (Original work published 2018)