| Number | Reference |
|---|---|
| P1 | [1] |
| P2 | [2] |
| P3 | [3] |
| P4 | [4] |
| P5 | [5] |
| P6 | [6] (In Chinese) |
| P7 | [7] (In Chinese) |
| P8 | [8] (In Chinese) |
| P9 | [9] (In Chinese) |
| P10 | This article |
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