Need a minimum measure: Pesachim 105b
The measure of wine is one which will produce a Reviit Amount on dilution: Shabbat 76b-77a; Eruvin 29b
Specifically of wine: Pesachim 107a
Once someone drinks from the cup, it is not usable: Pesachim 105b, 106a
Concern for a pitcher from which one has already drunk: Pesachim 106a
Concern for a barrel from which one has already drunk: Pesachim 106a
