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Mulholland CK, Diamond T, Ritchie A, Harvey C, Hanna WA.Mulholland CK, et al.Ulster Med J. 1990 Apr;59(1):90-2.Ulster Med J. 1990.PMID: 2349756Free PMC article.No abstract available.
Ritchie AJ, McManus K, McGuigan J, Stevenson HM, Gibbons JR.Ritchie AJ, et al.Postgrad Med J. 1992 Nov;68(805):892-5. doi: 10.1136/pgmj.68.805.892.Postgrad Med J. 1992.PMID: 1283632Free PMC article.