In a sense, the citation is the most fundamental truth claim that the historian makes: we agree that this object exists in the world. Interpretations will differ radically, but the citation establishes agreement that we (the writer and the readers) are on the same page.
The best way to keep track of your citations (e.g., books assigned in class, documents you found on an archival website for a research project, articles turned up in a literature review, etc.) is Zotero: a free, open source citation management tool. Zotero is strongly recommended for all of my classes and required for some of them.
Zotero is a popular tool, which means there are plenty of resources available for learning to use it properly. In brief: the application you download lives on your hard drive and you populate it with citations yourself. This “master” application allows you to quickly search and filter through all of the citations you have added to the local citation database.
Most people also use a browser extension (available for most web browsers, including Chrome, Firefox, and Safari). The extension simply “copies” data from an online repository to your local Zotero database. If the PittCat (or Amazon, or Google, or the Library of Congress) made any mistakes entering the bibliographic metadata, those mistakes will be reproduced on your local Zotero database.
The next piece of the puzzle is the word processor plugin, which may be automatically installed in Microsoft Word when you install Zotero (and there are plugins for other popular software, like Google Documents). This plugin saves you a lot of time properly formatting citations for a paper, or switching between citation schemas if need be.
Zotero also has extension. An especially useful one is ZotMoov, which will automatically rename PDFs and e-books based on Zotero citation data and move them to a folder of your choosing.
Finally, Zotero has a “social network” dimension in the form of cloud storage and “Zotero Groups,” i.e. shared libraries. Some classes use this feature for class assignments, which brings us to…
If you are participating in a collaborative bibliography building exercise, please abide by the following guidelines:
Always, always, always manually double check the citation information by looking at the original source. This means that if you used a browser extension to save yourself some time (not only fine, but recommended), you still have to proofread the copied citational information carefully.
Once you have the basic bibligraphic metadata correct, it is time to consider organization. Zotero organizes citation data by “collections” and “tags” — concepts you are likely familiar with from other contexts. Collections are a bit more like folders (though non-hierarchical, i.e. a citation can be in multiple collections at the same time) and represent a higher level of organization than tags (which work the same way they do on social media, more or less). The instructor will create collections: it is your job to decide which ones your shared citation should be added to. The tags are up to you, but put some thought into it. Tags that others have already used will be more useful, for instance. More specific tags will narrow down search results more, but are not very useful if they are so specific that they only apply to one entry.
Once you have the data correct, and after you have ensured that the citation is organized properly so that your colleagues can find it, now it is time to think about documentation. At the very least, you must attach one note to any citation you add. This note can be brief — a sentence, a short paragraph — but should offer some basic information about why you think the source or work you added is useful. For instance: “according to this review by Professor Professorson, this is the most important article about X or Y.”
You should also consider adding other attachments for greater context, such as URL links. For instance, if you originally learned about the citation you added from the footnotes of a Wikipedia article, why not attach a link to the referring article? (I.e., your citation object in Zotero would still be to the source itself, but you can add a link to as many websites or files as you like.)
Think of this step (along with the tags) as a “bread crumb trail”: you want to make sure your colleguages (not to mention your future self) can readily retrace your steps to figure out where the citation came from and why it is important.