1. API (American Petroleum Institute) 2003 a Test plan for reclaimed substances: streams containing naphthenic acids, phenolics, disulfides, acids or caustic. High Production Volume Chemical Programme. API Petroleum HPV Testing Group, 201-14906A, 15 Dec 2003 http://www.epa.gov/hpv/pubs/summaries/resbscat/c14906tp.pdf
2. API 2003 b Robust summary of information on reclaimed substances: naphthenic acid. American Petroleum Institute, 201-16126B, 15 Dec 2003 http://www.epa.gov/hpv/pubs/summaries/metalcarb/c14172rr10.pdf
3. API 2010 TSCA non-confidential business information, Doc No 8EHQ-10-18061A, Doc control No 88100000386, date received 8/9/10 http://www.epa.gov/oppt/tsca8e/pubs/8ehq/2010/aug10/8EHQ-0810-18061A (88100000386).pdf
4. API 2012 a Naphthenic acids category analysis and hazard characterization. American Petroleum Institute, Consortium registration # 1100997, 14 May 2012 http://www.epa.gov/hpv/pubs/summaries/resbscat/c14906ca5.pdf
5. API 2012 b Naphthenic acids category robust summaries. American Petroleum Institute, Consortium # 1100997, IUCLID data set, creation date 15 May 2012 http://www.petroleumhpv.org/docs/rec_subs/2012_may16_Naphthenic%20Acid%20Category%20RS%20May%2015%202012.pdf