Direct sensorimotor control for low-cost mobile tracking applications. - Denise M. Wilson; Eric Dennis Blom; Michael A. Marra II; Bruce Lanier Walcott (IEEE Trans. Ind. Electron., 2000)

Modified phase-frequency detector for improved response of PLL servo controller. - Christopher A. Adkins; Michael A. Marra II; Bruce Lanier Walcott (ACC, 2002)