Iwai, Masanobu, Soichiro Koyama, Kazuya Takeda, Yuichi Hirakawa, Ikuo Motoya, Hiroaki Sakurai, Yoshikiyo Kanada, Yohei Okada, Nobutoshi Kawamura, Mami Kawamura, and Shigeo Tanabe. “Effect of Lee Silverman Voice Treatment® BIG on the Major Motor Symptoms in Patients With Moderate Parkinson’s Disease: An Observational Study”. JOURNAL OF GERONTOLOGY AND GERIATRICS 72, no. 2 (May 27, 2024): 76-82. Accessed July 12, 2024. https://www.jgerontology-geriatrics.com/article/view/711.