The various sources include the scientific literature, books, government documents, and numerous external databases (such as PubChem, UniProt, PubMed, DrugBank, Human Metabolome Database (HMDB), NIST Chemistry WebBook, KEGG, NCI Database Browser, PharmGKB, Food and Drug Administration, ChEBI, and ChemExper).
In addition to various primary data formats (e.g. GPML, BioPAX, Reactome, KEGG), WikiPathways supports a variety of ways to integrate and interact with pathway content.