The primary source for adding kinos on Tisha B’av for other events is Rashi in Divrei Hayamim 35:25, Vayekonen Yirmiyahu al Yoshiyahu. Rashi talks about the kina that Yirmiyahu said on Yoshiyahu, and then he says that we say it on Tisha B’av “Dugmas hatzaros sh’iru byameinu”. That means that since all tzaros in the world have their roots in the churban and galus, we always add the kinos on Tisha B’av. Rashi is referring to kinos on crusades, which were the tzaros that happened in his day. Shaali Serufa ba’esh was written by Maharam Ruttenburg on the burning of 24 wagons of gemaros in Paris in the 13th century. The day for adding Kinos and aveilus is Tisha B’av.
Does anyone know of a link where I can view Tanach with Rashi? I’m doing this from memory, and I’d like to get it exact.