الإتاحة: https://doi.org/10.1007/bf00417181Test
الإتاحة: https://doi.org/10.1016/0031-9422Test(75)85196-xhttps://api.elsevier.com/content/article/PII:003194227585196X?httpAccept=text/xmlTesthttps://api.elsevier.com/content/article/PII:003194227585196X?httpAccept=text/plainTest