I have seen the theorem
A graph G is planar if and only if every subdivision of G is planar.
stated in many places. Often it is posed as an assignment or as part of a lecture.
I would like to reference the theorem and its proof in a paper. What should I use as my reference? Is there a textbook or article that comes to mind?
Yes, what comes to mind as a citable reference is Proposition 10.3 in