https://dds.las.ac.cn/service/document?appId=a1vacbnPuv9qJRzJvdNXfsesj9JbIa6e&appKey=sPBA4vANLzjnW1k5eufEcc4k7dxfNraW&ts=1763029722866&signature=a3803f60c143092264fe4c95a271d40b&articleTitle=Functional+Analysis+Methods+in+Numerical+Analysis&articleAuthor=M.+Z.+Nashed&publicationTitle=Functional+Analysis+Methods+in+Numerical+Analysis&language=&publicationType=1&publishYear=1979&isn=9783540091103&publisher=Springer+Berlin+Heidelberg