well you know any info you get is from an anti-mormon site and if it were true, the mormon chruch would not put out this info to pro tect joseph smith memory, I already looked on lds.org and could not find such info except for emma, and you and I know Joseph smith saw an angel with a sword come to him and tell him that he would be killed if he did not practise it, at least in my UT mormon history, this is what I was taught, but once again, I was never told the name, just brigham young's wives because of the beehive house. If thsi happen, it was probably form some jewish practise were the brother took his dead brother's wife to be his wife, and in this case the prophet took the other prophet's wives, to be his.