الوصول الحر: https://doaj.org/article/5dbb2234d8f24276a1a0965cf6215e2eTest
الوصول الحر: https://doaj.org/article/079156d0041a4c42acafaec995b75adaTest
الإتاحة: http://nar.oxfordjournals.org/content/36/1/e1.full-text-lowres.pdfTest