How to get location of a pdf file opened in preview

I have opened a pdf file in preview, without knowing where this file is located. How can I find out?

Simply ⌘+Click on it's name in the title bar or secondary click (right click) on it .

(I have a polish OS X on the screenshot)

1. Command+O this opens a dialogue with the current file.
2. Select the file, and press Command+R, this reveals the file in Finder.
3. In Finder, select the file, and press Option+Command+C, this copies the full path to the Clipboard.

Mojave - just click on the name, it will reveal the popup window with location. Alternatively, you can hover the cursor over the name - it will invoke a little downward arrow - click on it and you'll see the same popup with location.