f6b amp; acdnat=1402644608_6e10dd7e57fbd1d54a81a83045556435. Accessed October 6, 2014.
.http: //ac.els-cdn/S1026309812000727/1-s2.0-S1026309812000727-main.pdf? _tid=c1c96a24-f2cc - 11e3-bc3c - 00000aab0f27 amp; acdnat=1402644879_5e2faf1449f599e8e63671ca1bcca6e4. Accessed October 6, 2014.