1. AIA vitality. https://www.aiavitality.com.sg/memberportal/partners/fitbit
2. Fitbit. https://www.fitbit.com/
3. Health expenditure, total (% of GDP). https://data.worldbank.org
4. Manulife. https://www.manulifemove.hk/en/gift/
5. Bolton, P., Dewatripont, M.: Contract Theory. MIT Press, Cambridge (2005)