google book https://www.google.com/search?tbm=bks&q=The Ѕ͏u͏mm͏e͏r 3 B͏oo͏k S͏er͏ie͏s
hathitrust digital library https://babel.hathitrust.org/cgi/ls?q1=The Ѕ͏u͏mm͏e͏r 3 B͏oo͏k S͏er͏ie͏s&field1=ocr&a=srchls&ft=ft&lmt=ft
The British Library https://bll01.primo.exlibrisgroup.com/discovery/search?query=any,contains,The Ѕ͏u͏mm͏e͏r 3 B͏oo͏k S͏er͏ie͏s&tab=LibraryCatalog&search_scope=Not_BL_Suppress&vid=44BL_INST:BLL01&lang=en&offset=0