http://www.bbc.co.uk/schools/gcsebitesize/ict/system/1implementingrev1.shtml
http://www.igcseict.info/theory/8/analyse/index.html
http://igcseict.net/systems_analysis_and_design/analysis_overview.php
http://www.teach-ict.com/gcse/theory/syslifecycle/miniweb/pg4.htm
http://www.digitalist.org/Igcse/11-08_systems/11-08-1_analysis/11-08-1_analysis.htm
http://www.igcseict.info/theory/8/analyse/index.html
http://igcseict.net/systems_analysis_and_design/analysis_overview.php
http://www.teach-ict.com/gcse/theory/syslifecycle/miniweb/pg4.htm
http://www.digitalist.org/Igcse/11-08_systems/11-08-1_analysis/11-08-1_analysis.htm