The phrase "existing articles" is correct and usable in written English.
You can use it when referring to articles that are currently available or already published.
Example: "The research was based on existing articles in the field of environmental science."
Alternatives: "current articles" or "published articles".
However, most of the existing articles only studied the existence and uniqueness of mild solutions for evolution equations with nonlocal conditions, there are very few papers considered the regularity results for nonlocal evolution equations.
However, we observed that all of the existing articles are only devoted to the study of the existence, uniqueness, and controllability of mild solutions for fractional evolution equations; up to now the continuous dependence of mild solutions on parameters for fractional evolution equations has not been considered in the literature.
The next step was launching all the existing articles in their new format and new urls.
The existing Articles of Confederation were too weak for the task, and the founders cast about for alternative models.
"Some of the amendments contradict existing articles, and many of the articles give enough rights to the president to become another pharaoh".
Our paper enriches some known existing articles.
Discarding the existing Article 9 is discarding the existing peace.
The compromise resolution drew on an existing article in the 1998 Rome Statute under which the International Criminal Court was created, declaring that for one year, the court would not open proceedings against any United Nations peacekeeping personnel from countries that do not accept the court.
Our existing article deals with the literature review demonstrating the current progress and prospects of caspase studies in sepsis caused by infectious process.
Improve an existing article.
Remember, you can always add to an existing article, too.
