MLA

Okawa, et al. Opll: Ossification of the Posterior Longitudinal Ligament. Springer Singapore, 2020.

APA

Okawa, O., Iwasaki, M., Kawaguchi, Y., & Matsumoto, M. (2020). OPLL: Ossification of the Posterior Longitudinal Ligament. Springer Singapore.

Chicago

Okawa, Motoki Iwasaki, Yoshiharu Kawaguchi, and Morio Matsumoto. OPLL: Ossification of the Posterior Longitudinal Ligament. : Springer Singapore, 2020.