Prevent the (tentative) submission of an existing doi

[jypeter]

We wanted to add doi:10.5194/cp-17-1065-2021. this morning, and we discovered, after having added the abstract and painstakingly all the CMIP5 and CMIP6 related keywords, models, and variables that ... the doi was already referenced and we had done all this for nothing :-(

There should be an error message when you use Submit and then Search a doi that is already referenced. And possibly give the contact information of the person who submitted the doi

I have just ran into the same problem with https://doi.org/10.5194/cp-17-37-2021! I did have a look at the available Kageyama publications first and did not find this reference on the Hub. Trouble is that I had not scrolled down far enough for this publication to appear :-( I guess I should have used the Search button...