Open Mathematics
Open Mathematics > 2003 > 1 > 3 > 284-291
Open Mathematics > 2009 > 7 > 3 > 493-505
Open Mathematics > 2012 > 10 > 2 > 775-787
Open Mathematics > 2003 > 1 > 3 > 284-291
Open Mathematics > 2009 > 7 > 3 > 493-505
Open Mathematics > 2012 > 10 > 2 > 775-787