Hartigan, John (24 October 2005). Odd Tribes: Toward a Cultural Analysis of White People. Duke University Press Books. ISBN 978-0-8223-3584-9 ^ Okafor, Udoka
ne-talks-germany-war-enters-critical-phase-2022-04-25/ 1 May 2022閲覧。 ^ Okafor, Chiamaka (27 April 2022). “Four African countries invited to U.S-led Ukraine