array(5) { [0]=> string(16) "Isaac Elishakoff" [1]=> string(18) " Demetris Pentaras" [2]=> string(115) " Christina Gentilini-Mechanics of Functionally Graded Material Structures-World Scientific Publishing Co (2015).pdf" [3]=> string(8) " 9015765" [4]=> string(21) " 2018-03-15 17:28:2 " }