Found 1 pathways with zero (PubMed) references
* [http://classic.wikipathways.org/instance/WP300_r71890](http://classic.wikipathways.org/instance/WP300_r71890) 'Histone modifications' in Mus musculus has zero references;
More details at https://www.wikipathways.org/WikiPathwaysCurator/ReferencesTests/atLeastOneReference