Yibbum Procedure
Please note that "Yibbum" is the Torah's term for "Levirate Marriage." A "yavam" is a man who is eligible to perform Yibbum, and a "yevamah" is a woman who is eligible to perform Yibbum.
How
The Ketubah in a case of Yibbum
Completing the marriage "transaction" via intercourse: Kiddushin 2a, 4b [2x], 5a, 5b, 9b, 13b-14a
The youngest age at which the above works: Kiddushin 10a
Whether the marriage can be transacted via exchange of money or a legal document: Kiddushin 4b [2x], 9b, 14a
Whether her acquiescence is necessary for the transaction: Kiddushin 5a, 5b, 14a
Problems
Is there a financial penalty [אגרת מרד] for a woman or man who refuses yibbum or chalitzah: Ketuvot 64a
If one of the males who is eligible for Yibbum performs kiddushin with the yevamah's sister before Yibbum is done: Megillah 18b
If the woman claims, during the first 30 days, that the Brother-in-Law has not had sexual relations with her: Yevamot 111b, 111b-112a
If the woman claims, after the first 30 days, that the Brother-in-Law has not had sexual relations with her: Yevamot 111b, 111b-112a
Above two cases, where he admits that she is telling the truth: Yevamot 111b, 111b-112a
If she says there were sexual relations, and he denies it: Yevamot 112a
The yibbum status of the former co-wife of a woman who did yibbum and now claims that there were no sexual relations: Yevamot 112a
Bringing an asham taluy offering for possible guilt, and divorcing due to possible incest, if a yevamah performs yibbum within three months of her first husband's death, and then has a child seven months after her re-marriage: Keritot 17b-18a
