https://dds.las.ac.cn/service/document?appId=a1vacbnPuv9qJRzJvdNXfsesj9JbIa6e&appKey=sPBA4vANLzjnW1k5eufEcc4k7dxfNraW&ts=1763013324030&signature=0232ae88cd1a9484245f59b3562358b3&articleTitle=Symmetries+and+Laplacians&articleAuthor=Gurarie%2C+D.&publicationTitle=Symmetries+and+Laplacians&language=&publicationType=1&publishYear=&isn=9780444886125&publisher=