TY - JOUR A1 - Kasahara, A.K. A1 - Singh, R.J. A1 - Noymer, A. T1 - Vitamin D (25OHD) serum seasonality in the United States Y1 - 2013 DO - 10.1371/journal.pone.0065785 JF - PLoS One VL - 8 IS - 6 ER -