Where does the source data of Greengenes?

Question

[youname]

Hello community,
Can anyone tells me source data of Greengenes(http://greengenes.lbl.gov/cgi-bin/JD_Tutorial/nph-Tutorial_2Main2.cgi)?

I've read the Greengene's article and it seems to have used ARB Database.. that means that it originally comes from Silva?

Thanks