@article {Ogawa1998,
	title = {{Preservation of biogenic opal-A in earliest Cretaceous radiolarian claystone from the western Pacific}},
	journal = {Journal of Sedimentary Research, Section A: Sedimentary Petrology and Processes},
	volume = {68},
	number = {3},
	year = {1998},
	pages = {435{\textendash}439},
	issn = {1073-130X},
	url = {http://jsedres.geoscienceworld.org/cgi/content/abstract/68/3/435},
	author = {Ogawa, Y and Kawata, T}
}
