Migration matters

http://www.bbc.co.uk/education/guides/zkg82hv/revision/5

http://www.bbc.co.uk/schools/gcsebitesize/geography/migration/migration_trends_rev2.shtml

Padma vibhushan Shree Jayant Vishnu Narlikar jee

http://www.iucaa.ernet.in/~arp/album/arrow_of_time_jvn.htm

http://meghnad.iucaa.ernet.in/~jvn/