It is tempting to copy a few paragraphs of wikipedia in a newly created item. It is tempting to copy a page from a book which is precisely explaining what this new item is about with far more clarity then we have.
But is it not a good practice. Kneaver is not about keeping as much information as we can, it is not to constitute quickly a book like an encyclopedia. Kneaver is about learning and landmarking our knowledge.
Texts found in books, articles, blogs or Wikipedia are too well written to become part of your boot knowledge. They are made of long sentences with plenty of details. You want to keep in Kneaver only the substance of it. You can copy one, two sentences but not whole paragraphs. The best is to read it, several times and write what you memorized from it. Possibily you can compare by reading again the source text (not by having them side by side) and realizing you missed some important aspects relevant to your quest.
Articles typically explore all aspects of a subject. Kind of lateral thinking. Many of those aspects are not relevant t your goal, go and trim them. While it is aa good practie of the writer to cover completely his subject, it is your good practice to keep your texts lean and streamlined.
Think twice before you keep a quote or place it in a sub item. Sub items like comments are made for second reading.
Books or articles feature lists. lists of points, of questions, or caracteristics. That’s often useful to integrate but again keep it short and trim the labels. Only keep enough text so that you can double braket them and use them as seeds of new knowledge. When it will be their turn to be detailled you will already be more acquainted to the subject and possibly able to write your definition, using your terms and even most important it will be defined relatively to your context.
A special case is for items you want to express in great details because you want to share them. This is usually pieces of knowledge you acquired some while ago and are now integral part of your knowledge. The question of keeping it lean is not relevant anymore because it is in you head, once for all. In this case you are using Kneaver as a teaching plafeform. Often the item has become also clumsy because as you became more familiar with it you added details, links and comments.This is a case where items can become long and redacted. However there is a solution to keep both the lean body and the new redacted body: move the old contents in a comment before replacing with the new text.
There could be also copyright issues when copying. Copying for private use or short passage are considered as faire use but this outside my scope. Lateral thinking of my own:)
If you are really pressed by time you can just copy key terms and put forward to set their definition. It seems that what is the most important are links and not body of text.