Skandaraja, S.S.2016-06-232016-06-232015Skandaraja, S.S. 2015. Lesson 18: Treating a water sample using alum and sunlight, In: Practical Manual for GCE A/L Biosystem Technology Teachers. Ministry of Education and University of Kelaniya, Sri Lanka. 123-125 pp.978-955-4563-50-6http://repository.kln.ac.lk/handle/123456789/13658enLearning Object