Ruben, J., Wenzel, R., Obrig, H., Villringer, K., Bernarding, J., Hirth, C., Heekeren, H., Dirnagl, U., & Villringer,
A. (1997). Haemoglobin oxygenation changes during visual stimulation in the occipital
cortex. Advances in Experimental Medicine and Biology, 428,
181-187.