@article {1315031,
	title = {Fractioning Polymer Microspheres as Highly Accurate Density Standards},
	journal = {Analytical Chemistry},
	volume = {87},
	year = {2015},
	note = {1258},
	month = {5/22/15},
	pages = {7485-7491},
	chapter = {7485-7491},
	keywords = {density standards, density gradient centrifugation, aqueous multiphase systems, magnetic levitation, polymer microspheres},
	author = {Bloxham, W. H. and Hennek, J. W. and Kumar, A. A. and Whitesides, G. M.}
}
