If more than one source for a paraphrased idea is cited in a parenthetical citation, in what order do I list the sources?

If you paraphrase a single idea from more than one source and the sources are equally important, the order in which you list them is up to you. To be neutral, you might list them alphabetically: 

While reading may be the core of literacy, literacy can be complete only when reading is accompanied by writing (Baron 194; Jacobs 55).

But if some sources are more relevant to the idea than others, you might list the sources in order of relevance:

Scholars have long advanced the idea that political and economic forces undergird how narratives are shaped (Jameson; Poovey; Cohen).