USA Looking for Citation: expense classification

[Dave In Capital]

I'm looking for authoritative literature or -even better- analogous case law on classifying an expense based on its core purpose. I think of materiality considerations, but also I think there's IAS language on the general nature of an expense. For example, if the marketing manager occasionally engages in HR-related duties, that wouldn't warrant redefining the position as HR. And it isn't to an extent that would warrant an apportionment either. I would like to be able to say based on these guidance and case law, the users of financial statements would be misled by categorizing the position as anything other than marketing manager. Thanks in advance.