no difference, cel's is the closest to actually being written correctly.
a common mistake is for companies to copy how iforce originally wrote it, with it having to 17beta positions filled. there is only one 17b spot, and it has to be 17 beta hydroxy for it to work.
and the excuse, "we're fooling the fda" isn't fooling anyone. they know what it really is, and now you got two laws broken "failing to register a new medicine or w/e", and "intentionally mislabeling a product"