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• http://dlmf.nist.gov/about/news/#S1.I1.i1
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• http://dlmf.nist.gov/./26
• http://dlmf.nist.gov/./27
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• http://dlmf.nist.gov/./30
• http://dlmf.nist.gov/./31
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• http://dlmf.nist.gov/./33
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