Book Koma-script

[Hesham Kamel]

Hi,
Please, how can you make references appear in the Bibliography section
according to the order they appeared within text.
I mean I am using the Book Koma-Script class with plain style.
The problem is that the first text to appear is as, for example:
.........it is a measure of automobile's safety [6].
How can you sort them according to appearance in the text.
Thanks,
-- 
Hesham