Leitner, S., Voigt, C., Garcia-Segura, L. M., Van't Hof, T. J., & Gahr, M. (2001). Seasonal activation and inactivation of song motor memories in wild canaries is not reflected in neuroanatomical changes of forebrain song areas. Hormones and Behavior, 40(2), 160-168. doi:10.1006/hbeh.2001.1700.