Pishbin, T. , Firoozabadi, S. , Dabanloo, N. , Mohammadi, F. , Koozehgari, S. (2010), 'Effect of Physical Contact (Hand-Holding) on Heart Rate Variability', World Academy of Science, Engineering and Technology, Open Science Index 46, International Journal of Biomedical and Biological Engineering, 4(10), 521 - 525.