I'm using igraph in academic research and I need to provide a proper citation for the algorithm used in the components() command. This algorithm returns the connected components of the graph. The command in question is documented here. It's part of the R/CRAN igraph library.
I think the algorithm used is the one below, which seems to be the canonical workhourse algoirthm cited on the Wikipedia page for connected components.
Hopcroft, J.; Tarjan, R. (1973), "Algorithm 447: efficient algorithms for graph manipulation", Communications of the ACM, 16 (6): 372–378, doi:10.1145/362248.362272
Does anyone know what algorithm is used?