F. R. Lourenço, F. L. Francisco, M. R. S. Ferreira, T. de J. Andreoli, R. Löbenberg, and N. Bou-Chacra, “Design Space Approach for Preservative System Optimization of an Anti-Aging Eye Fluid Emulsion”, J Pharm Pharm Sci, vol. 18, no. 3, pp. 551–561, Oct. 2015.