Of course, the Guide is merely best practices, and is not a statement of the law.

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"It is no secret that in recent weeks, the leadership, finances and business practices of the NBPA have been questioned, " the organization said in a statement that acknowledged the subpoena and the investigation.

WSJ: U.S. Probes NBA Players Union

Chesapeake Energy said in a statement that it will pay the fines and has improved its cementing and casing practices since the investigation.

FORBES: Pennsylvania Pins Record Fine on Shale-Gas Producer