الإتاحة: http://dyuthi.cusat.ac.in/purl/4028Test
الإتاحة: https://doi.org/10.1006/fsim.2000.0278Testhttp://dyuthi.cusat.ac.in/purl/728Test
الإتاحة: http://dyuthi.cusat.ac.in/purl/3788Test