We have spared the technical details for this section, in which we are going to
explain several rather general techniques based on bucket sorting.
-As we have already suggested in the proof of Lemma \ref{contbor}, contractions
+As we have already suggested in the proof of Lemma \ref{contiter}, contractions
can be performed in linear time by building an~auxiliary graph and finding its
connected components. We will thus take care only of the subsequent flattening.