1. Britannica Online. https://www.britannica.com/topic/happiness.
2. Webster Online. https://www.webster-dictionary.org/definition/Happiness#:~:text=WordNet%20Dictionary,Synonyms%3A%20felicity
3. Stevenson K, Eli Schwartz E (2021) Relationship between happiness and GDP per Capita growth
4. The World Counts. https://www.theworldcounts.com/purpose/four-levels-of-happiness
5. Vaux A (1988) Social support: theory, research and interventions. Praeger, My, NY