References:

1: Duckworth A, Gross JJ. Self-Control and Grit: Related but Separable Determinants of Success. Curr Dir Psychol Sci. 2014 Oct;23(5):319-325. PubMed PMID: 26855479; PubMed Central PMCID: PMC4737958.

2: Eskreis-Winkler L, Shulman EP, Duckworth AL. Survivor mission: Do those who survive have a drive to thrive at work? J Posit Psychol. 2014 Jan 1;9(3):209-218. PubMed PMID: 24748898; PubMed Central PMCID: PMC3987915.

3: Eskreis-Winkler L, Shulman EP, Beal SA, Duckworth AL. The grit effect: predicting retention in the military, the workplace, school and marriage. Front Psychol. 2014 Feb 3;5:36. doi: 10.3389/fpsyg.2014.00036. eCollection 2014. PubMed PMID: 24550863; PubMed Central PMCID: PMC3910317.

4: Duckworth AL, Peterson C, Matthews MD, Kelly DR. Grit: perseverance and passion for long-term goals. J Pers Soc Psychol. 2007 Jun;92(6):1087-101. PubMed PMID: 17547490.

5. https://jamesclear.com/grit

6. The compound effect. Darren Hardy, Success Media, 2010