Fox, MA, "2,4-ETHANOTETRABORANE DERIVATIVES .2. SYNTHESIS, CHARACTERIZATION, AND GAS-PHASE STRUCTURES OF 2,4-(MECHCH(2))B4H8, 2,4-(TRANS-MECHCHME)B4H8, AND 2-PR-2,4-(MECHCH(2))B4H7 AND 4-PR-2,4-(MECHCH(2))B4H7", Inorganic Chemistry, 1995