“…Traditional extractive summarization methods are mostly unsupervised (Radev et al, 2000;Lin and Hovy, 2002;Wan, 2008;Wan and Yang, 2008;Hirao et al, 2013;Parveen et al, 2015;Yin and Pei, 2015;Li et al, 2017;Zheng and Lapata, 2019), utilizing a notion of sentence importance based on n-gram overlap with other sentences and frequency information (Nenkova and Vanderwende, 2005), relying on graph-based methods for sentence ranking (Erkan and Radev, 2004;Mihalcea and Tarau, 2004), or performing keyword extraction combined with submodular maximization (Tixier et al, 2017;Shang et al, 2018).…”