2.5 References (ordered from 'user understandable' to protocol description):
http://www.juniper.net/documentation/en_US/junos12.1/topics/concept/igmp-snooping-multicast-
forwarding.html
https://en.wikipedia.org/wiki/Internet_Group_Management_Protocol
http://wiki.mikrotik.com/wiki/Manual:Multicast_detailed_example
https://tools.ietf.org/html/rfc2236
https://tools.ietf.org/html/rfc3376
2.5 Video Tutorial:
https://www.youtube.com/watch?v=GGqcwdDW1a8 (Cisco Multicast IGMPv2)
2.6 Dumb tool, which can act as IGMP Querier application:
https://code.google.com/p/igmpquery/