I cannot even begin to imagine what implements of destruction a wolverine has that could bring down a moose. That is indeed a credible cite but I suspect them of leaving out crucial details.
“A [pack of] wolverine[s] has been known to kill a [newborn sickly] moose [that was sleeping.]”
Anyway, I remember reading somewhere that a natural predator of the wolverine is the mountain lion. I’d say a hyena is at least equal to a mountain lion in terms of wolverine ownage.