Redirect Notice
 The previous page is sending you to https://www.sciencedirect.com/science/article/pii/S0007153682800120/pdf?md5=e3f0ab44c65a9c66fb2e709ab1194f2c&pid=1-s2.0-S0007153682800120-main.pdf.

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