what are verb tenses?- an academic source

[antlost]

Dear TEFL community,
You can laugh at me, but for one month I have not found what verb tenses are.
I have a project about verb tenses. At first, I think it is easy to find a definition of verb tenses on English websites, but later the more I read the more complex the matter is. I have not found an academic source such as a reliable book mentioning what verb tenses are.
Hence, if you have met the definition of verb tenses in a reliable source, please tell me.

Thanks so much! Have you have a nice day and remember I'm looking forward hearing news from you soon!

[Lucy]

Have you looked at books by Michael Swan? I think there's one called Practical English Usage: it's an excellent grammar reference.

[Laila]

Verb tenses are tools that English speakers use to express time in their language. You may find that many English tenses do not have direct translations in your language. The word tense comes from the Latin word, tempus, which means "time." The tense of a verb shows the time when an action or condition occurred. In English the tense also may provide emphasis and may determine whether or not an action or condition was continuous or repetitive.