+
+#### References
+
+- [Apache/PHP - error log per VirtualHost - StackOverflow](http://stackoverflow.com/q/176)
+- [Apache - PHP: php_value vs php_admin_value and the use of php_flag explained](https://ma.ttias.be/php-php_value-vs-php_admin_value-and-the-use-of-php_flag-explained/)
+- [Server-side TLS (Apache) - Mozilla](https://wiki.mozilla.org/Security/Server_Side_TLS#Apache)
+- [Nginx Beginner's guide](http://nginx.org/en/docs/beginners_guide.html)
+- [Nginx ngx_http_fastcgi_module](http://nginx.org/en/docs/http/ngx_http_fastcgi_module.html)
+- [Nginx Pitfalls](http://wiki.nginx.org/Pitfalls)
+- [Nginx PHP configuration examples - Karl Blessing](http://kbeezie.com/nginx-configuration-examples/)
+- [Apache 2.4 documentation](https://httpd.apache.org/docs/2.4/)
+- [Apache mod_proxy](https://httpd.apache.org/docs/2.4/mod/mod_proxy.html)
+- [Apache Reverse Proxy Request Headers](https://httpd.apache.org/docs/2.4/mod/mod_proxy.html#x-headers)
+- [HAProxy documentation](https://cbonte.github.io/haproxy-dconv/)
+- [Nginx documentation](https://nginx.org/en/docs/)
+- [`X-Forwarded-Proto`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-Proto)
+- [`X-Forwarded-Host`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-Host)
+- [`X-Forwarded-For`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For)
+- [Server-side TLS (Nginx) - Mozilla](https://wiki.mozilla.org/Security/Server_Side_TLS#Nginx)
+- [How to Create Self-Signed SSL Certificates with OpenSSL](http://www.xenocafe.com/tutorials/linux/centos/openssl/self_signed_certificates/index.php)
+- [How do I create my own Certificate Authority?](https://workaround.org/certificate-authority)
+- [Travis configuration](https://github.com/shaarli/Shaarli/blob/master/.travis.yml)
+- [PHP: Supported versions](http://php.net/supported-versions.php)
+- [PHP: Unsupported versions (EOL/End-of-life)](http://php.net/eol.php)
+- [PHP 7 Changelog](http://php.net/ChangeLog-7.php)
+- [PHP 5 Changelog](http://php.net/ChangeLog-5.php)
+- [PHP: Bugs](https://bugs.php.net/)
+- [Transport Layer Security](https://en.wikipedia.org/wiki/Transport_Layer_Security)
+- Hosting providers: [DigitalOcean](https://www.digitalocean.com/) ([1](https://www.digitalocean.com/docs/droplets/overview/), [2](https://www.digitalocean.com/pricing/), [3](https://www.digitalocean.com/docs/droplets/how-to/create/), [How to Add SSH Keys to Droplets](https://www.digitalocean.com/docs/droplets/how-to/add-ssh-keys/), [4](https://www.digitalocean.com/community/tutorials/initial-server-setup-with-debian-8), [5](https://www.digitalocean.com/community/tutorials/an-introduction-to-securing-your-linux-vps)), [Gandi](https://www.gandi.net/en), [OVH](https://www.ovh.co.uk/), [RackSpace](https://www.rackspace.com/), etc.
+
+