@article {Vogel-1994-NPU,
	author=		"S. Vogel",
	journal=	"Amer. Sci.",
	pages=		"464--471",
	title=		"{Nature's Pumps}",
	volume=		"82",
	year=		"1994",
	theme=		"natural",
	project=	"",
	added-by=	"Daniel Acevedo",
	date-added=	"Wed February 18 13:00:09 2004"
}
@article {Vogel-1994-NPU-url,
	author=		"S. Vogel",
	journal=	"Amer. Sci.",
	note=		" \url{http://vis.cs.brown.edu/results/bibtex/Vogel-1994-NPU.bib}{(bibtex: Vogel-1994-NPU)}",
	pages=		"464--471",
	title=		"{Nature's Pumps}",
	volume=		"82",
	year=		"1994",
	theme=		"natural",
	project=	"",
	added-by=	"Daniel Acevedo",
	date-added=	"Wed February 18 13:00:09 2004"
}