Suliman AM, Ali AO, A.A. Idriss SE, Abdualrahman MA. A Comparative Study on Red and White Karkade (Hibiscus sabdariffa L.) Calyces, Extracts and Their Products. Pak. J. Nutr. 2011;10(7):680–683. doi:10.3923/pjn.2011.680.683