noun
Used when looking at something for information or guidance, such as a document, website, or another person's opinion. Often appears in compounds like 参考書 (reference book) and 参考になる (to be helpful as a reference).
この本はレポートを書くときの参考になった。
This book was a helpful reference when I wrote my report.
参考
For your reference, I am sending last year's data.