Found 1 pathways with zero (PubMed) references
* [http://classic.wikipathways.org/instance/WP269_r116923](http://classic.wikipathways.org/instance/WP269_r116923) 'Heme biosynthesis' in Drosophila melanogaster has zero references;
More details at https://www.wikipathways.org/WikiPathwaysCurator/ReferencesTests/atLeastOneReference