Brent A, Goedkoop M, Itsubo N, Jolliet O, Mueller-Wenk R, Peña C, Schenk R, Stewart M, Weidema B P (2003). Final report of the LCIA definition study. Life Cycle Impact Assessment programme of The UNEP/SETAC Life Cycle Initiative https://2-0-lca.com/?p=17887