As I could found in here how the transpile works in qiskit, I understood that transpile gets arbitrary Unitary gate $U$ and some set of basis gates as input, and produce some quantum circuit of $U$ implemented with those basis gates.
So, I understood this transpile process as some sort of 'synthesis' problem that has been shown in some literature, but I can't find which synthesis method does Qiskit implemented for their transpile process. Will there be any references or docs that I can refer to?