A SF B means 'activity A must start before activity B finishes' (or 'B can't finish until A has started').(Project work started) SS (Project management activities started).A SS B means 'activity A must start before activity B can start' (or 'B can't start until A has started').(Last chapter written) FF (Entire book written).A FF B means 'activity A must finish before activity B can finish' (or 'B can't finish before A is finished').A FS B means 'activity A must finish before activity B can begin' (or 'B can't start until A has finished').There are four standard types of dependencies: The A Guide to the Project Management Body of Knowledge (PMBOK Guide) does not define the term dependency, but refers for this term to a logical relationship, which in turn is defined as dependency between two activities, or between an activity and a milestone. In a project network, a dependency is a link among a project's terminal elements. Relationship in which one task of a project requires another to be completed first
