• The unconvenient truth on AI in eHealth.  - https://www.nature.com/articles/s41746-019-0155-4 
• Filling the gap in a patient's medical data. -  https://news.mit.edu/2019/machine-learning-incomplete-patient-data-0125
• Health cares failure to share data -  https://academyhealth.org/blog/2019-09/health-cares-failure-share-data-issue-culture-or-crisis-integrity
• Some centralized health data in USA exist now.  - https://www.technologyreview.com/2021/06/21/1026590/us-covid-database-n3c-nih-privacy/
• https://hdsr.mitpress.mit.edu/pub/l7a2t45s/release/1 
• https://hdsr.mitpress.mit.edu/pub/3uc0p5dq/release/2
• https://ec.europa.eu/health/latest-updates/general-guidelines-guidelines-electronic-exchange-health-data-under-cross-border-directive-201124eu-2022-06-10_en
• https://www.twobirds.com/en/insights/2022/germany/the-european-health-data-space-proposal-of-the-european-commission
• https://www.oecd.org/health/health-systems/Empowering-Health-Workforce-Digital-Revolution.pdf