close minimized windows

I am running OSX 10.8.5.

I need to open a lot of text file. Sometimes I minimize some of their windows. At some point, I want to close them (but not all of them) when they are still minimized and shown as icons on Dock. When I right click on those icon, there is only one option which is to "Open....". This really drives me crazy.

What is the best and quick and intuitive way to close these minimized windows, please help me.