https://dds.las.ac.cn/service/document?appId=a1vacbnPuv9qJRzJvdNXfsesj9JbIa6e&appKey=sPBA4vANLzjnW1k5eufEcc4k7dxfNraW&ts=1763049474854&signature=0b47d6bf840b7ab4633de304060a943a&articleTitle=Combinatorial+and+Geometric+Group+Theory&articleAuthor=Oleg+Bogopolski%2C+Inna+Bumagin%2C+Olga+Kharlampovich%2C+Enric+Ventura&publicationTitle=Combinatorial+and+Geometric+Group+Theory&language=&publicationType=1&publishYear=2010&isn=9783764399108&publisher=Birkh%C3%A4user+Basel