Which recording artist released its fourth studio album, titled Ether, which featured a guest appearance from singer, songwriter and rapper CeeLo Green?
Ether (B.o.B album):  The album features guest appearances from Lil Wayne, Young Thug, T.I., Big K.R.I.T., Ty Dolla Sign, Usher, CeeLo Green, Young Dro, and more.
i don't know