Restrict file access to specific web pages nginx

I want to allow access a folder and its files only to a specific web page with nginx. I already tried that

location /live {
    valid_referers none blocked server_names *.some.tk;
    if ($invalid_referer) {
        return 403;
    }
}

When I try to open some.tk/live it returns 403 but specifying a file does not.

How can I solve that?

Thanks in advance.