Sung, T., Buchholz, R., Casson, F. J., Fable, E., Grosshauser, S., Hornsby, W. A., Migliano, P., & Peeters, A. G. (2013). Toroidal momentum transport in a tokamak caused by symmetry breaking parallel derivatives. Physics of Plasmas, 20:. doi:10.1063/1.4799750.