AMS online bibliographic links

[StevanWhite]

The AMSBIB package has special commands for several online bibliographic systems. It would be good to somehow support all these in BibLaTeX, to avoid the alternative of a big messy URL.

See "Short user’s guide to the AMSBIB package", Table 2,

• \crossref{...} DOI (Digital Object Identifier)
• \mathnet{...}Math-Net.Ru (Russian mathematical portal)
• \mathscinet{...} MathSciNet (Mathematical Reviews of the American Mathematical Society)
• \zmath{...} zbMATH (Zentralblatt MATH abstracting and reviewing system)
• \adsnasa{...} ADS NASA (Astrophysics Data System)
• \isi{...} Web of Science by Thompson Reuters

I don't know if these fit the BibLaTeX eprint mechanism, as they aren't really for a URL resolution system.

For example, I have used this declaration

\def\mathnettourl#1{http://mi.mathnet.ru/eng/#1}
\DeclareFieldFormat{eprint:mathnet}{%
  mathnet\addcolon\space
  \ifhyperref
    {\href{\mathnettourl#1}{\nolinkurl{#1}}}
    {\nolinkurl{#1}}}
\DeclareFieldAlias{eprint:MATHNET}{eprint:mathnet}
\DeclareFieldAlias{eprint:MathNet}{eprint:mathnet}

so that a bibliography entry containing fields

  eprint =      "dan/v329/i5/p547",
  eprinttype =  {mathnet},

produces a URL http://mi.mathnet.ru/eng/dan/v329/i5/p547 but in the PDF it is displayed as mathnet:dan/v329/i5/p547.

Note that in the case of MathNet, the string eng/ in the URL brings up English descriptive information, while rus/ brings up Russian.