European drug report 2020 : trends and developments . Luxembourg :  Publications Office of the European Union , 2020 . 69 s . ISBN 978-92-9497-545-4 . ISSN 1977-9860
https://www.emcdda.europa.eu/system/files/publications/13236/TDAT20001ENN_web.pdf . [1, z toho požičaných 0]