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Hawken MJ, Parker AJ.Hawken MJ, et al. Among authors: parker aj.Proc R Soc Lond B Biol Sci. 1987 Jul 22;231(1263):251-88. doi: 10.1098/rspb.1987.0044.Proc R Soc Lond B Biol Sci. 1987.PMID: 2889214