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Czeisler CA, Johnson MP, Duffy JF, Brown EN, Ronda JM, Kronauer RE.Czeisler CA, et al. Among authors: duffy jf.N Engl J Med. 1990 May 3;322(18):1253-9. doi: 10.1056/NEJM199005033221801.N Engl J Med. 1990.PMID: 2325721Free article.
Czeisler CA, Dumont M, Duffy JF, Steinberg JD, Richardson GS, Brown EN, Sánchez R, Ríos CD, Ronda JM.Czeisler CA, et al. Among authors: duffy jf.Lancet. 1992 Oct 17;340(8825):933-6. doi: 10.1016/0140-6736(92)92817-y.Lancet. 1992.PMID: 1357348
Czeisler CA, Chiasera AJ, Duffy JF.Czeisler CA, et al. Among authors: duffy jf.Exp Gerontol. 1991;26(2-3):217-32. doi: 10.1016/0531-5565(91)90014-d.Exp Gerontol. 1991.PMID: 1915692Review.
Czeisler CA, Kronauer RE, Allan JS, Duffy JF, Jewett ME, Brown EN, Ronda JM.Czeisler CA, et al. Among authors: duffy jf.Science. 1989 Jun 16;244(4910):1328-33. doi: 10.1126/science.2734611.Science. 1989.PMID: 2734611