These are the official API 1509 documents. See the first one (engine-oil licensing and certification system), pages 74, 131, and 135. 0W-16 is explicitly part of API SP. GF-6B is restricted to 0W-16 only, and you can't even have 5W-16 in GF-6B.
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There is a lot of detail on licensing in the beginning of the document. I didn't go through the tables in pages 74 and 135, but I'm pretty sure API SP with Resource Conserving in the SAE 0W-16 viscosity grade is equivalent to ILSAC GF-6B.