Missing references

[trappitsch]

The original RILIS database stated for some schemes in the notes that the DOI needs to be added. This entry was deleted from the actual database and this issue is here in order to replace those remarks on the website. The following schemes (with new labels) will need updating with a DOI:

Overall, all of these schemes are associated with this reference: K. Wendt at the virtual workshop "Atomic Structure of Actinides & Related Topics" (26.-28.05.2021)

• Th-2
• Cm-1
• Cf-1
• Es-1

This issue is mostly for Katerina.