Data flow diagram
Good intro. from SmartDraw: http://www.smartdraw.com/resources/tutorials/data-flow-diagrams/#/resources/tutorials/Introduction-to-DFD Tutorial: http://www.hit.ac.il/staff/leonidm/information-systems/ch24.html
Good intro. from SmartDraw: http://www.smartdraw.com/resources/tutorials/data-flow-diagrams/#/resources/tutorials/Introduction-to-DFD Tutorial: http://www.hit.ac.il/staff/leonidm/information-systems/ch24.html