Please clarify your question. Do you ask if the author should provide references, or if the Times prints them? In order, answers are yes, and no. But any references you email should probably avoid web links, which editors will be reluctant to open for concern over computer viruses.
If you're asking if the Times includes sources to background information in their opinion writing, then the answer is yes. All good opinion writing includes background information to back up the claims being made.
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