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de Vries JI, Visser GH, Prechtl HF.de Vries JI, et al. Among authors: prechtl hf.Early Hum Dev. 1988 Jan;16(1):85-103. doi: 10.1016/0378-3782(88)90089-8.Early Hum Dev. 1988.PMID: 3278881
de Vries JI, Visser GH, Prechtl HF.de Vries JI, et al. Among authors: prechtl hf.Early Hum Dev. 1985 Nov;12(2):99-120. doi: 10.1016/0378-3782(85)90174-4.Early Hum Dev. 1985.PMID: 3905353