Graham Klyne, Jacob Palme. Registration of Mail and MIME Header Fields. RFC, 4021:1-54, March 2005. [doi]
@article{rfc4021, title = {Registration of Mail and MIME Header Fields}, author = {Graham Klyne and Jacob Palme}, year = {2005}, month = {March}, doi = {10.17487/RFC4021}, url = {https://doi.org/10.17487/RFC4021}, researchr = {https://researchr.org/publication/rfc4021}, cites = {0}, citedby = {0}, journal = {RFC}, volume = {4021}, pages = {1-54}, }