Redirect Notice
The previous page is sending you to
https://www.sciencedirect.com/science/article/pii/S0007153686802157/pdf?md5=1c7033b3679a99a2e72e3c7542db3aa2&pid=1-s2.0-S0007153686802157-main.pdf
.
If you do not want to visit that page, you can
return to the previous page
.