«Test for Past Infection». Centers for Disease Control and Prevention, 11-02-2020. Arxivat de l'original el 16 maig 2020. [Consulta: 19 maig 2020]. «Antibody blood tests, also called antibody tests, check your blood by looking for antibodies, which show if you had a previous infection with the virus. Depending on when someone was infected and the timing of the test, the test may not find antibodies in someone with a current COVID-19 infection.»
Ward, Dan (May 2020). «Sampling Bias: Explaining Variations in Age Distributions of COVID-19 Cases». Technical Report (WardEnvironment). doi:10.13140/RG.2.2.27321.19047/2.
«Test for Past Infection». Centers for Disease Control and Prevention, 11-02-2020. Arxivat de l'original el 16 maig 2020. [Consulta: 19 maig 2020]. «Antibody blood tests, also called antibody tests, check your blood by looking for antibodies, which show if you had a previous infection with the virus. Depending on when someone was infected and the timing of the test, the test may not find antibodies in someone with a current COVID-19 infection.»