Journal of Mathematical Analysis and Applications, 285 (2003), 506-527 http://ac.els-cdn.com/S0022247X03004219/1-s2.0-S0022247X03004219-main.pdf?_tid=d93d7390-61f2-11e4-ad7a-00000aacb361&acdnat=1414865818_dfb5c7ea110ffe3a70b90b9e5d8cabbb
