Scrollbar on the left

Is there a deep study that suggests to place a scrollbar on the right? Personally I move it to the left whenever possible (Firefox allow this, as well as xterm and emacs).

I know that placing a scrollbar on the left is considered useful only while typing in "right-to-left" languages like Hebrew, but premises for this are unknown to me.

In the screenshots of NeXT desktop, for example, you can see that scrollbars are always on the left side and there are only English characters.