2019 and 2020 data arrived

The data for IEEE VIS 2019 and 2020 is now finally in and complete, including the internal references. Note that I (Petra Isenberg) now use a new process to automatically extract the internal citations as well as the citation counts that IEEEXplore doesn't export anymore. As it relies on pdf parsing, errors can happen. Leave comments for corrections if you spot anything.

I also fixed a bug in the deduped author name column where some papers had incorrect authors.