言及 and 引用: mentioning a topic and quoting wording
Compare references to a cost issue or research direction with a sentence quoted from a diary. Preserve the scope of barely mentioning and of a request to mark a quotation.
Referring to a topic
言及 (げんきゅう) means mentioning or referring to a topic. 「報告書は費用の問題にほとんど言及していない。」 says the report barely addresses the cost issue.
In 「講演の最後に、研究の今後について短い言及があった。」, there was a brief reference to the research’s future at the end of the lecture. Brevity belongs to this example, not to every mention.
Bringing in original wording
引用 (いんよう) means quotation or citation. In 「自分の日記から短い一文を引用した。」, a short sentence was quoted from the speaker’s own diary.
「引用した部分には印を付けてください。」 asks for a mark on the quoted section. Having quoted material and having finished marking it are separate facts.
The topic and the source of wording
Mentioning the future of research does not by itself show that another sentence was reproduced. Quoting a diary sentence identifies wording brought in from that source.
ほとんど言及していない does not mean that the issue receives absolutely no mention. Quoting content also does not by itself establish the quoting person’s agreement with it.
What should be marked in 「引用した部分には印を付けてください。」?
Show the answer and why
The quoted section. The request does not require marking the entire text or every topic mentioned, and it does not report that the marking is complete.