doi:10.1039/C2EE22596D. (原始内容存档于2014-02-09). NREL 2013: Blending hydrogen into natural gas pipeline networks: A review of key issues (PDF). [2020-07-14]
Hydrogen Europe. [2020-10-15]. (原始内容存档于2020-11-21). NREL 2013: Blending hydrogen into natural gas pipeline networks: A review of key issues (PDF). [2020-10-26]