<math>D_+</math> and <math>D_-</math> are the stay/stay (<math>F_{0}</math>), and swap/swap (<math>F_{2}</math>) coefficients (equation (36)).<br>
<math>\zeta</math> and <math>\Psi</math> are parameters that enable the free precession frequencies to be written in a more concise form (equation (12)).<br>
Note that in reference 2[http://dx.doi.org/10.1016/S0076-6879(01)39315-1 10.1016/S0076-6879(01)39315-1], in equation 25, the definition used for ?cp is twice that used in this work but is otherwise identical.
== Parameters ==