Widget listing category posts by author?

Hi there,
i need to show in the sidebar of a specific page a list of posts of a category and written by an author.
I am just using Widget Logic to filter the category to list and to specify the page where show it and it works like a charm. But i also need to show the same list filtered also by the author of the article.
How can i do that? Does exists a plugin or a widget?

Thanks!!!