- *
- * See "Digital Communication Receivers: Synchronization, Channel
- * Estimation and Signal Processing" by Heinrich Meyr, Marc Moeneclaey, & Stefan Fechtel.
- * ISBN 0-471-50275-8.
+ * The complex version here is based on:
+ * Modified Mueller and Muller clock recovery circuit
+ * Based:
+ * G. R. Danesfahani, T.G. Jeans, "Optimisation of modified Mueller and Muller
+ * algorithm," Electronics Letters, Vol. 31, no. 13, 22 June 1995, pp. 1032 - 1033.