HALVORSON, Karin. Inside your germs. Minneapolis, Minnesota : Super Sandcastle, an imprint of Abdo Publishing, [2016]. ©2016. 1 online zdroj (32 stran). Dostupné na internetu: <http://search.ebscohost.com/login.aspx?direct=true&db=nlebk&AN=1081833&lang=cs&site=eds-live&ebv=EB&ppid=pp_A> ISBN 9781680770681.