Redirect Notice
 The previous page is sending you to https://www.sciencedirect.com/science/article/pii/S0007153687800669/pdf?md5=69af9910cfbc375761cc0baa22be3ede&pid=1-s2.0-S0007153687800669-main.pdf.

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