Documenting papers well and knowing the precise format for citing print and electronic resources demands attention. Check with your professor for the preferred bibliography style. It is likely that the requisite style will be that of the Modern Language Association (MLA) or perhaps the Humanities version of The Chicago Manual of Style. Whichever style you use, it's important that you are consistent; there should be no changes from one documentation system to another within a paper.
Bibliographic citation management tool can assist you in creating personal collections of citations by easily importing references from databases. These references can then be inserted into papers. See a comparison of different Citation Tools including Zotero.