How explain non-secure google site as referer?
Why are websites requiring referer headers (and failing silently)?
$_SERVER['HTTP_REFERER'] is used to check if links is clicked in browser ? how to check if link is cliked in email viewer?
How to ensure of a referrer to a website?
When does Google include the user's query (q= in the query string of HTTP_REFERER) when they link to you?
Can I programmately set the referer header of a request?
How to activate http referer from server / cpanel?
How reliable is HTTP_REFERER?
HTTP Referer on HTML Frames
What would HTTP referrer be?
is it possible to know where the user is coming from when he uses the back button?
in what situation does the HTTP_REFERER not work?
Which browsers/plugins block HttpReferer from being sent? [closed]
How do you spoof HTTP_REFERER?