Calculating the 9th of Av as the date of the Above occurrence: Taanit 29a
The Establishment of the 9th of Av as a date for crying through the generations, as a result of the Desert Generation's pointless crying: Taanit 29a
Gd didn't speak to Moshe from the sin of the Spies until the generation dying for that Sin died out: Taanit 30b
On the 15th of Av, the people dying for the Sin with the Spies stopped dying: Taanit 30b
[Possible] Retraction of Hashem's Oath Barring the Generation of the Desert from entering Israel: Chagigah 10a
The desert generation were considered to be ex-communicated from Heaven, but they still practiced sexual relations and sent Temple Offerings via a Proxy: Moed Katan 15b
Whether Tzelafchad was one of those who died for attempting to go to Israel after Gd said that the generation could not enter: Shabbat 97a