Zotero / z oʊ ˈ t ɛr oʊ / is a free and open-source reference management software to manage bibliographic data and related research materials (such as PDF files). Notable features include web browser integration, online syncing, generation of in-text citations, footnotes, and bibliographies, as well as integration with the word processors Microsoft Word, LibreOffice Writer, and Google Docs. Zotero is a free Evernote alternative that makes jotting down ideas on the canvas as easy as it gets. Collecting, organizing, citing and sharing materials from the web happens effortlessly inside. Zotero is a standalone (and browser app) that allows note-taking, citation, and collection/management of online sources. It is useful for a researcher and allows sharing and collaboration. With Zotero you can attach notes and images to citations, create collections, and create endnotes and bibliographies in many citation styles (including. An active community of Zotero users has developed a variety of plugins to provide enhancements, new features, and interfaces with other programs. To install a plugin in Zotero, download its.xpi file to your computer. Then, in Zotero, click “Tools → Add-Ons”, then drag the.xpi for the plugin onto the Add-Ons window that opens.
DOI's are required (if available) if you use APA style, and are valuable tools for your Zotero library (EndNote, Mendelay, and other reference management sopftware applications as well, I believe) as you can paste in a DOI and have it automatically create a bibliographic record for the article/dataset/chapter/whatever. DOIs can also be an important tool for alternative methods of promoting and determining the spread and impact of scholarly work ('altmetrics') because they provide a common reference link. and you can search by them to get to the article/chapter/etc.

Zotero Evernote Integration System
CrossRef is Crossref is 'an official Digital Object Identifier Registration Agency of the International DOI Foundation' and manages most academic journal DOIs: 'Crossref makes research outputs easy to find, cite, link, assess, and reuse. We’re a not-for-profit membership organization that exists to make scholarly communications better.'
Zotero Plugin
DOI example: 10.1186/s13059-014-0424-0 (they can be longer or shorter, and include letters)
Zotero Evernote Integration Solutions
Page link: https://libguides.libraries.wsu.edu/zotero/doi
