N. A. Alarfaj1 and M. F. El-Tohamy2, “Comparative Potentiometric Study Using Modified 2-Hydroxypropyl b-Cyclodextrin and Modified Carbon Nanotubes Sensors for Determination of Ambroxol Hydrochloride”, ajc, vol. 26, no. 24, pp. 8640–8648, Dec. 2014.