Redirect Notice
 The previous page is sending you to https://www.sciencedirect.com/science/article/pii/0305197880900010/pdf?md5=a71f59b4929b02fdf896129d2b133a7f&pid=1-s2.0-0305197880900010-main.pdf.

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