What is the best place to get BibTeX entries for ICLR and other machine learning papers? dblp seems the best i found so far (as also mentioned in the comments and in What is the best place to get BibTeX entries for computer science articles ?) but even there some papers from NIPS workshops and ICLR in general are not listed as such and are listed simply as CoRR papers.

For example "Neural Machine Translation by Jointly Learning to Align and Translate" 
https://dblp.uni-trier.de/rec/bibtex/journals/corr/BahdanauCB14 
although after writing the question i'm finding that most papers are referencing the NMT paper also as CoRR/arXiv. I also didn't find proceedings of ICLR so maybe it's a general issue only with ICLR papers and some conference workshops.
For NeurIPS (previously NIPS), the NeurIPS website itself is a good source: look for a paper, go to its page, and click on the "BibTex" link. Here is a random sample (!):





ICML, COLT, and JMLR appear to have similar BibTex-ready websites: see http://proceedings.mlr.press/. For instance, going to the abstract of a randomly chosen paper from ICML'15:





ICLR does not seem to have this in place; for instance, even checking on Google Scholar, the paper you point out is cited a lot (~4k times), but always as the arXiv version. For conferences or workshops using OpenReview, such as ICLR'18 (I believe it was the first time for this conference), you can get some BibTex entry by clicking on a specific paper, and selecting "Show BibTex":

However, it is unclear to me the resulting citation is better that the ArXiv one.