Correct semantic use of markup

[adam3smith]

This one may be on me, so I'll fix this, but there's a semantic distinction between <i> and <em>

<em> is used for emphasis and tools that use semantic information (like screenreaders) will interpret it this way: For example: We should really get to this soon.

<i> is used for stylistic italics, such as for species names and, most relevant here, book and journal titles.