Sometimes, having LESS experience is helpful. I took the question at face value with no regard for semantics.

"Can a non persisted computed column reference column(s) that are NOT in the same table as the computed column.?"

I saw no reason it could not, but the question got me thinking... WHY would it be bad to reference columns from another table? I began to think about normalization and the fact that maybe the computed column might belong somewhere else, especially if ALL the columns in the UDF came from the same table. I cannot think of a real world example right now where this would make sense. That is just the path my brain went down...