Matti Nykänen

Evaluation of repeatability of pressure algometry on the neck muscles for clinical use.

Jari Ylinen, Arja Häkkinen, Hannu Kautiainen, 2007, Manual therapy.

Active neck muscle training in the treatment of chronic neck pain in women: a randomized controlled trial.

Jari Ylinen, Olavi Airaksinen, Arja Häkkinen, 2003, JAMA.