Evaluating SARS-CoV-2 spike and nucleocapsid proteins as targets for antibody detection in severe and mild COVID-19 cases using a Luminex bead-based assay, Mariën, Joachim, Ceulemans Ann, Michiels Johan, Heyndrickx Leo, Kerkhof Karen, Foque Nikki, Widdowson Marc-Alain, Mortgat Laure, Duysburgh Els, Desombere I, et al. , Journal of Virological Methods, Jan-02-2021, Volume 288, (2021)