A manual for writers of research papers, theses, and dissertations, 7th edition - Kate L. Turabian 2007

Don't plead ignorance, misunderstanding, or innocent intentions
Drafting your report
Part I. Research and writing: from planning to production

To be sure, what looks like plagiarism is often just honest ignorance of how to use and cite sources. Some students sincerely believe that they don't have to cite material they have downloaded from the Web if that material is free and publicly available. But they're wrong. The fact that it's public or free is irrelevant. You must cite anything you use that was created by someone else.

Many students defend themselves by claiming they didn't intend to mislead. The problem is, we read words, not minds. So think of plagiarism not as an intended act but as a perceived one. Avoid any sign that might give your readers any reason to suspect you of it. Whenever you submit a paper with your name on it, you implicitly promise that you wrote every word that you don't clearly and specifically attribute to someone else.

Here is the best way to think about this: If the person whose work you used read your report, would she recognize any of it as hers, including paraphrases and summaries, or even general ideas or methods? If so, you must cite that source and enclose any sequence of her exact words in quotation marks or set them off in a block quotation.