Minimal Risk
The concept of minimal risk is especially influential in the US debate, not least because it is enshrined in the so-called Code of Federal Regulations containing rules governing research on human subjects.. The concept of minimal risk also has a crucial status in Art.17 II of the Convention on Human Rights and Biomedicine of the Council of Europe.
Council of Europe (1997): Convention for the Protection of Human Rights and Dignity of the Human Being with regard to the Application of Biology and Medicine: Convention on Human Rights and Biomedicine. https://www.coe.int/en/web/conventions/full-list?module=treaty-detail&treatynum=164
On research involving minors:
Code of Federal Regulations. Title 45 "Public Welfare". Subtitle A - Department of Health and Human Services. Part 46 "Protection Of Human Subjects". Revised June 23, 2005. Online Version
Research regarding a risk minimisation model:
Maio, Giovanni (2002): Ethik der Forschung am Menschen. Zur Begründung der Moral in ihrer historischen Bedingtheit. Stuttgart-Bad Cannstatt: frommann-holzboog (Medizin und Philosophie 6).