Before I finished my undergraduate thesis, my supervisor had asked me to write a smaller paper with the same content as my thesis and send it to a conference. Now, my thesis ended and my paper is going to be published. Should I cite my undergraduate thesis in my paper? Because undergraduate theses are not easily accepted as a references.
As suggested by @MartinČerný I'm turning my comment into an answer. I'd include the thesis in the bibliography and write in the paper (perhaps in a footnote) something like "This paper is an abridged version of the author's undergraduate thesis [reference here], written under the supervision of [adviser's name here]."