https://dds.las.ac.cn/service/document?appId=a1vacbnPuv9qJRzJvdNXfsesj9JbIa6e&appKey=sPBA4vANLzjnW1k5eufEcc4k7dxfNraW&ts=1763029742875&signature=1d69b678a2adfad33645d9057363463e&articleTitle=Convex+Variational+Problems&articleAuthor=Michael+Bildhauer&publicationTitle=Convex+Variational+Problems&language=&publicationType=1&publishYear=2003&isn=9783540402985&publisher=Springer+Berlin+Heidelberg