Nonlinear piezoelectric effect in the purple membrane of bacteriorhodopsin.

Kietis, P., Valiokas, R., Lingė D. and Valkunas, L., Nonlinear piezoelectric effect in the purple membrane of bacteriorhodopsin., Liet. fiz. zur. (Lith. J. Phys.,) 38 (1):93-97 1998