I am looking for a file which contains all CDS for their NM (coding transcript) identifiers. Ensembl has one which maps each of its ENST's to their CDS, however I have been unable to find the same for Refseq's coding transcripts (NM). If anyone knows of and could point me to such a file, that would be great. It doesn't even have to come from RefSeq databases. Perhaps there are other NCBI db's which have the file I'm looking for?