Redirect Notice
 The previous page is sending you to https://www.sciencedirect.com/science/article/pii/0261219489900963/pdf?md5=fea89388cacf89a69f635c4471d0b422&pid=1-s2.0-0261219489900963-main.pdf&_valck=1.

 If you do not want to visit that page, you can return to the previous page.