Several exceptions have been formally codified, which are of a nature germane to the day and/or to mourning.
Is it permissible, therefore, for one to study Holocaust responsa on Tish'ah BeAv? That is, may one study the questions and answers presented during (and preserved since) the Nazi Holocaust, in which Jews were confronted with situations that not only tested their life and faith, but also the limits of Jewish law? If so, is this generally practiced (do Shuls and Yeshivoth tend to offer classes on these subjects, and/or are these subjects included as recommended study in various communities)?
A written source one way or another would be preferred, but anecdotal evidence of a practice one way or another would be interesting, and possibly useful, as well.