S. Kungsanan, S. Kittisrisawai, B. Kitiyanan, T. Rirksomboon, S. Osuwan, and J. F. Scamehorn, “Recovery of Alcohol Ethoxylates Nonionic Surfactant using Co-Current Vacuum Stripping”, ASEAN J. Chem. Eng., vol. 11, no. 1, pp. 22-27, Dec. 2011.