Perinatal risk factors for neonatal encephalopathy: an unmatched case-control study by Tann, C, Nakakeeto, M, Willey, B, Sewegaba, M, Webb, E, Oke, I, Mutuuza, E, Peebles, D, Musoke, M, Harris, K, Sebire, N, Klein, N, Kurinczuk, J, Elliott, A, Robertson, N