[Rd] DOI query

[Koenker, Roger W]

Recent package checking revealed that the CUP DOI for my QR book 
https://doi.org/10.1017/CBO9780511754098
is DOA so I duly wrote to CUP and the initial response is:  

> We would like to extend our gratitude for reporting this problem with your title. We are currently working on fixing all the DOI links affected by the ebooks.cambridge.org decommission, but I am afraid that we do not have an estimated date for when they will all be working as intended again, due to the complexity of the issue.

I wondered if anyone had a suggestion for an alternative way to reference such things?  And incidentally  wondered whether DOI links were often this flaky.  I was led to believe that DOIs were like Platonic solids always there when you needed them.