Graph Connectivity and Termilogies

Connectivity in a directed graph
http://www.geeksforgeeks.org/connectivity-in-a-directed-graph/

BiConnected Graph
http://www.geeksforgeeks.org/biconnectivity-in-a-graph/

Articulation Points (or Cut Vertices) in a Graph
http://www.geeksforgeeks.org/articulation-points-or-cut-vertices-in-a-graph/

Bridges in a Graph
http://www.geeksforgeeks.org/bridge-in-a-graph/