PISA 2018 Assessment and Analytical Framework. Paris : OECD, 2019. 304 s. PISA. Available on Internet: <https://www.oecd-ilibrary.org/education/pisa-2018-assessment-and-analytical-framework_b25efab8-en> ISBN 978-92-64-94031-4. [Copy count : 1, currently available 0, at library only 1]