=== HTTP code : 200 ===

Response headers
================
HTTP/1.1 200 OK
Date: Tue, 06 Aug 2019 14:22:12 GMT
Server: Apache
Strict-Transport-Security: max-age=31536000; includeSubDomains; preload
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Request headers
================
HEAD /pubmed/18018689 HTTP/1.1
Host: www.ncbi.nlm.nih.gov
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Referer: https://bme.fiu.edu
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Link is valid.