TY - JOUR AU - Michael Nelson AU - Mary Bedner AU - Brian Lang AU - Blaza Toman AU - Katrice Lippa C2 - Analytical and Bioanalytical Chemistry DA - 2015-09-07 DO - https://doi.org/10.1007/s00216-015-9013-7 LA - en M1 - 407 PB - Analytical and Bioanalytical Chemistry PY - 2015 TI - Metrological approaches to organic chemical purity: primary reference materials for vitamin D metabolites ER -