N,O6-partially acetylated chitosan nanoparticles hydrophobically-modified for controlled release of steroids and vitamin E
J.P. Quiñones, K.V. Gothelf, J. Kjems, Á.M.H. Caballero, C. Schmidt, C.P. Covas, Carbohydrate Polymers 91 (2012) 143–151.

Self-assembled nanoparticles of glycol chitosan – Ergocalciferol succinate conjugate, for controlled release
J.P. Quiñones, K.V. Gothelf, J. Kjems, Á.M.H. Caballero, C. Schmidt, C.P. Covas, Carbohydrate Polymers 88 (2012) 1373–1377.

Self-assembled nanoparticles of modified-chitosan conjugates for the sustained release of dl-;1-tocopherol
J.P. Quiñones, K.V. Gothelf, J. Kjems, C. Yang, A.M.H. Caballero, C. Schmidt, C.P. Covas, Carbohydrate Polymers 92 (2012) 856–864.

Novel drug delivery systems: Chitosan conjugates covalently attached to steroids with potential anticancer and agrochemical activity
J. Pérez Quiñones, R. Szopko, C. Schmidt, C. Peniche Covas, Carbohydrate Polymers 84 (2010) 858–864.