Practicing and competitions
World memory championship links
http://www.world-memory-statistics.com/calculator.php
http://hongkongmemorychampionships.com/tc/papers/events_binary.pdf
http://www.worldmemorysportscouncil.com/papers.asp
http://www.world-memory-statistics.com/worldrankings.php
Apps
https://play.google.com/store/apps/details?id=com.Tester&hl=en
https://itunes.apple.com/gb/app/memory-school/id723568462?mt=8
Mnemonic Systems
http://www.academictips.org/memory/noshape.html
http://en.wikipedia.org/wiki/Mnemonic_major_system
http://mt.artofmemory.com/wiki/Person-Action-Object_(PAO)_System
Facebook Groups
https://www.facebook.com/groups/135189819963302/?fref=nf
Other useful links
http://www.random.org/integers/