Found one of the links: http://dicephysics.info/0107.htm
There is also conflicting evidence on the 'ones' issue. Some people have done a study indicating the opposite is true, determining that centrifugal force (spin) beats gravity. But, what these conflicting issues point out is that the way in which that die is thrown is going to skew the results (with gaming dice, casino dice have most consistently been studied and determined to be fair). So if you throw the cheap round cornered dice with drilled pips in a manner that favors centrifugal motion (by tossing or throwing), apparently 'ones' are more likely (according to one study I found). However, if dice are dropped, minimizing centrifugal force, then the weight (mass*gravity) exerts more influence. The link I included above does indicate that six is more likely than one with the cheap dice, but 2-5 are actually more common than both, which makes me think I was correct in what I guessed about the destabilization on the 1-6 pole. But that study does not indicate the quality of the dice roll.