Notes from the Field: COVID-19 Case Investigation and Contact Tracing Program - Spirit Lake Tribe, North Dakota, September-November 2020. - Matthias J; Charboneau T; Schaffer C; Rusten J; Whitmer S; de la Paz J; Dykstra J; Pathmanathan I; Stowell D (MMWR. Morbidity and mortality weekly report, 2021)