Redirect Notice
 The previous page is sending you to https://www.sciencedirect.com/science/article/pii/0002939467941098/pdf?md5=a8781fac0b1d2d465c1b27747effdcce&pid=1-s2.0-0002939467941098-main.pdf.

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