Kevin Loria. (2017, 13 July), 7 of the filthiest things you touch all the time. Retrieved October 20, 2017, from http://www.businessinsider.com/dirtiest-objects-in-your-home-and-office-2017-7/#your-smartphone-1
KEVIN LORIA. (2017, 7 September), Here Are 6 of The Filthiest Things You Touch All The Time. Retrieved October 20, 2017, from https://www.sciencealert.com/here-are-7-of-the-filthiest-things-you-touch-all-the-time
The Institute for the Promotion of Teaching Science and Technology (IPST), Ministry of Education, a non-profit organization under the Thai government, developed SciMath as a website that provides educational resources in Science, Mathematics and Technology. IPST invites visitors to use its online resources for personal, educational and other non-commercial purpose. If there are any problems, please contact us immediately.