NCBI BioSystems Database - contents of last version available via FTP
Citing the NCBI BioSystems Database
  Geer LY, Marchler-Bauer A, Geer RC, Han L, He J, He S, Liu C, Shi W, Bryant SH. The NCBI BioSystems database. Nucleic Acids Res. 2010 Jan; 38(Database issue):D492-6. (Epub 2009 Oct 23) [PubMed PMID: 19854944] [Full Text] [PDF]  

Revised 15 April 2022