الإتاحة: https://doi.org/10.1016/j.pratan.2018.01.006Testhttps://api.elsevier.com/content/article/PII:S1279796018300068?httpAccept=text/xmlTesthttps://api.elsevier.com/content/article/PII:S1279796018300068?httpAccept=text/plainTest
الإتاحة: https://doi.org/10.1016/j.pratan.2011.05.004Testhttps://api.elsevier.com/content/article/PII:S1279796011000659?httpAccept=text/xmlTesthttps://api.elsevier.com/content/article/PII:S1279796011000659?httpAccept=text/plainTest