https://dds.las.ac.cn/service/document?appId=a1vacbnPuv9qJRzJvdNXfsesj9JbIa6e&appKey=sPBA4vANLzjnW1k5eufEcc4k7dxfNraW&ts=1763013060638&signature=fea41006dff70bb659584e709fcd138d&articleTitle=Space-Filling+Curves&articleAuthor=Hans+Sagan&publicationTitle=Space-Filling+Curves&language=&publicationType=1&publishYear=1994&isn=9780387942650&publisher=Springer+New+York