There are also different forms of citation for different disciplines.
You should say whether they are economic analysts, artists, physicists, etc.
If you do not know anything about the author, and cannot find any information, it is best to say where you found the source and why you believe it is credible and worth citing.
But often you can just tag this information onto the beginning or end of a sentence.
For example, the following sentence puts information about the author and work before the quotation: Milan Kundera, in his book The Art of the Novel, suggests that “if the novel should really disappear, it will do so not because it has exhausted its powers but because it exists in a world grown alien to it.” You may also want to describe the author(s) if they are not famous, or if you have reason to believe your reader does not know them.
Whenever you change the original words of your source, you must indicate that you have done so.
Otherwise, you would be claiming the original author used words that he or she did not use. You could accidentally change the meaning of the quotation and falsely claim the author said something they did not.
Most of the time, you can just identify a source and quote from it, as in the first example above.
Sometimes, however, you will need to modify the words or format of the quotation in order to fit in your paper.
For example, let's say you want to quote from the following passage in an essay called "United Shareholders of America," by Jacob Weisberg: The citizen-investor serves his fellow citizens badly by his inclination to withdraw from the community. He does so by focusing his pursuit of happiness on something that very seldom makes people happy in the way they expect it to.
When you quote, you generally want to be as concise as possible.