Consider the following references used in a research paper on the impact of social media on public health. Identify and correct all the errors in formatting according to APA style:

1. **Anderson, J. P., & Smith, K. (2019).** *Social media use in adolescence: A review of the evidence.* Journal of Adolescent Health, 55(3), 267-278. DOI: 10.1016/j.jadohealth.2019.04.013.

2. **National Institute of Mental Health. (2021).** Mental health and social media use: A longitudinal study. *https://www.nimh.nih.gov/research/research-funded/research-areas/population-based/mental-health-and-social-media-use-a-longitudinal-study.*

3. **Williams, L. (2020).** *Social media and youth mental health: A policy brief.*