1. Article 29 Working Party (2007) Opinion 04/2007 on the concept of personal data. https://ec.europa.eu/justice/article-29/documentation/opinion-recommendation/files/2007/wp136_en.pdf
2. Article 29 Working Party (2014) Opinion 05/2014 on anonymisation techniques. https://ec.europa.eu/justice/article-29/documentation/opinion-recommendation/files/2014/wp216_en.pdf
3. Bohannon J (2015) Privacy. Credit card study blows holes in anonymity. Science 347:468–468
4. Booth S, Jenkins R, Moxon D, Semmens N, Spencer C, Taylor M, Townend D (2004) What are ‘personal data’? A study conducted for the UK Information Commissioner, University of Sheffield. https://www.frareg.com/cms/wp-content/uploads/personal_data.pdf
5. Burgin M (2010) Theory of information. Fundamentality, diversity and unification. World Scientific Publishing, Singapore