I am a doctoral student and therefore have only little experience in publishing. Now I ask myself how I should deal with working papers of other researchers in my articles. I have read some interesting working papers and would like to quote them in my article. However, I am not sure if I should do so. Since these working papers have never been published and reviewed in a journal, I do not know if citing them is useful or even allowed. On the other hand there are interesting results in these articles, which I would like to mention.
So I would like to ask how I can best deal with working papers when citing.
Can I easily include and quote them in my text?
Or should I better not do so, because I would like to submit my own article later in a respected journal?