DOCUMENTATION: add markdown links in the readme files
It would be very nice to have the link to the ADS entry when a paper is cited.
This was done accordingly to Poppenhaeger et. al. (2020) 1, and we improved it while mixing with Tu et al. (2015) 2. You can also find ...
This is done like that:
This was done accordingly to Poppenhaeger et. al. (2020) [^Poppenhaeger-et-al-20],
and we improved it while mixing with Tu et al. (2015) [^Tu-et-al-20]. You can also find ...
[^Poppenhaeger-et-al-20]: [Poppenhaeger et. al. 2020](https://arxiv.org/abs/2005.10240)
[^Tu-et-al-20]: [Tu et. al. 2020](https://arxiv.org/abs/2005.10240)