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| btu-20220630.htm | 2606509 | 2022-08-04 16:25:00 |
| btu-20220630.xsd | 61603 | 2022-08-04 16:25:00 |
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| btu-20220630_htm.xml | 2016960 | 2022-08-04 16:25:00 |
| btu-20220630_lab.xml | 693594 | 2022-08-04 16:25:00 |
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| btu_20220630xex321.htm | 5754 | 2022-08-04 16:25:00 |
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