Avdievich, N., & Forbes, M. (1995). Dynamic Effects in Spin-Correlated Radical
Pair Theory: J Modulation and a New Look at the Phenomenon of Alternating Line Widths in the EPR Spectra of Flexible Biradicals. The Journal of Physical Chemistry, 99(24), 9660-9667. doi:10.1021/j100024a004.