30 second search results:Name any other paper the CDC cites for natural immunity then. It's only the one.

Coronavirus Disease 2019 (COVID-19)
CDC provides credible COVID-19 health information to the U.S.
So there's the first 10 referencing immunity and antibodies due to infection (ie: 'natural') from just that one brief. There's more from that brief, and there's God knows how many briefs/press releases/info pages/etc from the CDC over the past 1.5+ years.Jones, J., Percent population with antibodies due to vaccination only, vaccination and infection, or infection only (unpublished). 2021, Centers for Disease Control and Prevention.
Cromer, D., et al., Prospects for durable immune control of SARS-CoV-2 and prevention of reinfection. Nature Reviews Immunology, 2021. 21(6): p. 395-404.
Grigoryan, L. and B. Pulendran, The immunology of SARS-CoV-2 infections and vaccines. Semin Immunol, 2020. 50: p. 101422.
Post, N., et al., Antibody response to SARS-CoV-2 infection in humans: A systematic review. PLoS One, 2020. 15(12): p. e0244126.
Shrotri, M., et al., T cell response to SARS-CoV-2 infection in humans: A systematic review. PLoS One, 2021. 16(1): p. e0245532.
Cervia, C., et al., Systemic and mucosal antibody responses specific to SARS-CoV-2 during mild versus severe COVID-19. J Allergy Clin Immunol, 2021. 147(2): p. 545-557 e9.
Roltgen, K., et al., Defining the features and duration of antibody responses to SARS-CoV-2 infection associated with disease severity and outcome. Sci Immunol, 2020. 5(54).
Gudbjartsson, D.F., et al., Humoral Immune Response to SARS-CoV-2 in Iceland. N Engl J Med, 2020. 383(18): p. 1724-1734.
Dan, J.M., et al., Immunological memory to SARS-CoV-2 assessed for up to 8 months after infection. Science, 2021. 371(6529).
Wang, H., et al., Dynamics of the SARS-CoV-2 antibody response up to 10 months after infection. Cell Mol Immunol, 2021. 18(7): p. 1832-1834.
Where are you planning on moving the goal posts now?