[2425] Ryan, J., Croft K., Mori T., Wesnes K., Spong J., Downey L., et al. (2008).  An examination of the effects of the antioxidant Pycnogenol(R) on cognitive performance, serum lipid profile, endocrinological and oxidative stress biomarkers in an elderly population. J Psychopharmacol. 22(5), 553 - 562.

[862] Ryan, J. (1969).  Grouping and short-term memory: different means and patterns of grouping. The Quarterly Journal of Experimental Psychology. 21(2), 137 - 147.