Reference block [test][1] contains [google][http://www.google.co.uk] followed by [test][2] and [test][3]. Finally we have [test][4] and [google2][google].

[1]: http://www.google.co.uk

[http://www.google.co.uk]: http://www.google.co.uk

[2]: http://dsurl.stuff/something.jpg

[3]:http://www.google.co.uk

 [4]:http://www.google.co.uk

[google]: http://www.google.co.uk