Harald Tveit Alvestrand. Mapping between X.400 and RFC-822/MIME Message Bodies. RFC, 2157:1-49, January 1998. [doi]
@article{rfc2157, title = {Mapping between X.400 and RFC-822/MIME Message Bodies}, author = {Harald Tveit Alvestrand}, year = {1998}, month = {January}, doi = {10.17487/RFC2157}, url = {https://doi.org/10.17487/RFC2157}, researchr = {https://researchr.org/publication/rfc2157}, cites = {0}, citedby = {0}, journal = {RFC}, volume = {2157}, pages = {1-49}, }