Machine Translation journal

It's a Springer journal that ran from 1986 to 2021: https://link-springer-com.proxy.library.georgetown.edu/journal/10590/volumes-and-issues

We could consider linking to its articles.

No specific files or tests are named in this issue. First locate where journal/venue records and external links are stored, then find the template or renderer that exposes those links on journal pages. Add the Springer link for the Machine Translation journal in the same structure as other entries, and validate by running the project’s normal build/check workflow to confirm the journal now links to its articles.

由索引模型根据 Issue 内容生成。