The best replacement for doi is pmid.

The best alternatives to doi are rated as following:
★★★★★  pmid
★★★★  url
★★★★  doc
★★★★  issn
★★★  handle
★★★  jankovic
★★★  isbn
★★★  doi
★★  accession number
★  date krumm
★  puchkova
★  pii
★  masato yoshino
  krumm

Your alternative for doi is not listed? Suggest!
Speaking about doi, one probably shouldn't forget about apa format.

Other search terms related to doi and their ratings are:
★★★★★ apa format
★★★★★ apa
You have in mind a companion for doi and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of doi in all years. Click on graph for more.
doi
pmid
url