They list two references I think. The first is from the Journal Of Satifiability. The link appears empty to my browser but this link leads to an article of the

They list two references I think. The first is from the Journal Of Satifiability. The link appears empty to my browser but this link leads to an article of the same authros and the same journal; https://www.cs.uky.edu/~marek/papers.dir/11.dir/JSAT8_10_Weaver.pdf https://www.cs.uky.edu/~marek/papers.dir/11.dir/JSAT8_10_Wea... The second paper was from a conference originally and found this link to it through Google Scholar (also listed in another comment); http://t-news.cn/Floc2018/FLoC2018-pages/proceedings_paper_495.pdf http://t-news.cn/Floc2018/FLoC2018-pages/proceedings_paper_4...