[sk_kireeti]

They are not external subject, but external links. Let me explain it with a theoretical example for you. If the exam/question is to identify or diagnose a problem based on symptoms, then at a corner we can give link to sites which mentions which defect will have what problem. People giving exam can refer those sites before answering. Of course, if candidate don't know anything on subject, he will waste his time in searching that answer and ultimately fails. You can take this as a simulation to the US examination system when you are allowed to take text books to exam hall.

Thanks,
Krishna