I want to know the answer to the following question:
What may be doubled to indicate a long aspiration?
All the background I'm provided with is that "Hence, the two degrees of aspiration in Korean stops are sometimes transcribed ⟨kʰ kʰʰ⟩ or ⟨kʻ⟩ and ⟨kʰ⟩, but they are usually transcribed [k] and [kʰ], with the details of voice-onset time given numerically.". Is that enough to answer the question?
Answer: no