Ganehiarachchi, G.A.S.M.2016-06-232016-06-232015Ganehiarachchi, G.A.S.M. 2015. Lesson 28: Study and calibration of knapsack sprayer, In: Practical Manual for GCE A/L Biosystem Technology Teachers. Ministry of Education and University of Kelaniya, Sri Lanka. 203-209 pp.978-955-4563-50-6http://repository.kln.ac.lk/handle/123456789/13670enLearning Object