Search results
Applied Mathematics Letters > 2011 > 24 > 2 > 97-102
Rendiconti del Circolo Matematico di Palermo Series 00002 > 2010 > 59 > 1 > 151-159
Journal of Mathematical Analysis and Applications > 2007 > 328 > 2 > 821-829
Nonlinear Analysis > 2005 > 61 > 8 > 1295-1301