SCHLEICHER, Andreas. Schools for 21st - century learners : strong leaders, confident teachers, innovative approaches. Paris : OECD, 2015. 75 s. International summit on the teaching profession. Available on Internet: <http://www.oecd-ilibrary.org/education/schools-for-21st-century-learners_9789264231191-en> ISBN 978-92-64-23118-4.