1. General Data Protection Regulation (EU) 2016/679, Article 8(1): "Member States may provide by law for a lower age for those purposes provided that such lower age is not below 13 years."
2. European Data Protection Board (EDPB), Guidelines 05/2020 on consent under Regulation 2016/679, Version 1.1, 4 May 2020, Paragraph 136: "Article 8(1) GDPR provides that Member States may legislate to provide for a lower age, but not below the age of 13."
3. General Data Protection Regulation (EU) 2016/679, Recital 32: "Consent should be given by a clear affirmative act... Silence, pre-ticked boxes or inactivity should not therefore constitute consent."
4. General Data Protection Regulation (EU) 2016/679, Article 7(3): "The data subject shall have the right to withdraw his or her consent at any time... It shall be as easy to withdraw as to give consent."
5. Bygrave, L. A. (2020). The EU General Data Protection Regulation (GDPR): A Commentary. Oxford University Press. Chapter on Article 8, discussing the Member State margin of appreciation regarding the age of consent for minors. (ISBN: 978-0198826491).