Tumat Meit [Impurity of a Corpse] emerging from a Rooved Structure
Where the Entrance of the Structure has been sealed: Shabbat 146b
Where the structure of the sealed entrance has been destroyed: Shabbat 146b
The minimum size of the structure, to act as a block against vertical communication of impurity: Eruvin 30a; Succah 10a
Whether impurity will pass through a blockage of wet vegetation which would be valid for use as Bitter Herbs on Pesach Night: Succah 13b
Where the structure has many entrances: Eruvin 68a
Where the structure has many entrances, but only one is open: Eruvin 68a
Nullifying the impurity retroactively, once a person plans to remove the body via one of the entrances [before or after the death, depending on a debate in understanding the case]: Eruvin 68a; Beitzah 10a