Redirect Notice
The previous page is sending you to
https://www.sciencedirect.com/science/article/pii/S1434461099700404/pdf?md5=3fcb4ae2b11fd772056a018556cc5fda&pid=1-s2.0-S1434461099700404-main.pdf
.
If you do not want to visit that page, you can
return to the previous page
.