Tài liệu tham khảo WikiPedia: Max_Jacob http://cantic.bnc.cat/registres/CUCId/a11355840 http://data.rero.ch/02-A000092989 http://www.max-jacob.com http://catalogo.bne.es/uhtbin/authoritybrowse.cgi?... http://www.culture.gouv.fr/public/mistral/leonore_... http://katalog.nsk.hr/F/?func=direct&doc_number=00... http://uli.nli.org.il/F/?func=direct&doc_number=00... http://data.bibliotheken.nl/id/thes/p068884427 http://mak.bn.org.pl/cgi-bin/KHW/makwww.exe?BM=1&N... https://nla.gov.au/anbd.aut-an35239958
