# What are good resources to learn the basics of graph theory

I just spent half a day "debugging" a script that tried to get the betweenness centrality of a weighted graph with negative weights. However the package I used for that julia's LightGraphs uses Dijkstra's shortest paths, which require non-negative weights as input. I didn't know this, and thus wasted a lot of my and other peoples time trying to find out why my script didn't work.

I the end I found it out. But I figured it would be good to learn some basic graph theory to avoid this kind of problems in the future. Can anybody recommend a good [book|course|other resource] on graph theory? I don't look for a source that rigorously proves all kind of properties, but more of an overview. If I need to know more about a specific graph/test/metric I can always look it up later.