Twin directories of n4:

[DIR]  ftp://ftp.uni-leipzig.de/pub/linux/pub/comp/os/linux/slackware/slakware/n4/
[DIR]  ftp://ftp.swin.edu.au/slackware/slackware-3.3/slakware/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/TAC/volumes/1995/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/TAC/volumes/1996/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/TAC/volumes/1997/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/TAC/volumes/1998/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/TAC/volumes/1999/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/TAC/volumes/6/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/TAC/volumes/7/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/TAC/volumes/8/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/TAC/volumes/9/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/AASF/volumes/1995/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/AASF/volumes/1996/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/AASF/volumes/1997/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/AASF/volumes/1998/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/AASF/volumes/1999/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/AASF/volumes/6/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/AASF/volumes/7/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/HHA/volumes/1999/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/HHA/volumes/2000/n4/
[DIR]  ftp://ftp.ics.muni.cz/pub/EMIS/journals/HHA/volumes/2001/n4/
[DIR]  ftp://ftp.slackware.at/slackware-3.3/slakware/n4/
[DIR]  ftp://ftp.ctio.noao.edu/pub/tabbott/n4/
[DIR]  ftp://ftp.rz.tu-bs.de/pub/mirror/ALL_primary_servers/rsync/ftp.slackware.com/slackware/slackware-3.3/slakware/n4/
[DIR]  ftp://ftp.samba.org/pub/unpacked/n4/
[DIR]  ftp://64.50.238.52/.1/slackware/slackware-3.3/slakware/n4/
[DIR]  ftp://64.50.236.52/.1/slackware/slackware-3.3/slakware/n4/
[DIR]  ftp://147.52.159.12/mirrors/linux/slackware/slackware-3.3/slakware/n4/
[DIR]  ftp://ftp.tpnet.de/pub/pc/linux/suse80/suse/n4/
[DIR]  ftp://ftp.uni-wuppertal.de/pub/linux/slackware/slackware-4.0/slakware/n4/
[DIR]  ftp://ftp.uni-wuppertal.de/pub/linux/slackware/slackware-7.0/slakware/n4/
[DIR]  ftp://ftp.uni-wuppertal.de/pub/linux/slackware/slackware-7.1/slakware/n4/
[DIR]  ftp://ftp.uni-wuppertal.de/pub/linux/slackware/slackware-3.6/slakware/n4/
[DIR]  ftp://ftp.uni-wuppertal.de/pub/linux/slackware/slackware-3.9/slakware/n4/
[DIR]  ftp://ftp.uni-wuppertal.de/pub/linux/slackware/slackware-3.3/slakware/n4/
[DIR]  ftp://ftp.uni-wuppertal.de/pub/linux/slackware/slackware-3.4/slakware/n4/
[DIR]  ftp://ftp.uni-wuppertal.de/pub/linux/slackware/slackware-3.5/slakware/n4/
[DIR]  ftp://ftp.irf.se/pub/tmp/outgoing/slkw-1-2.8/n4/
[DIR]  ftp://ftp.embl-heidelberg.de/ftp.ebi.ac.uk/pub/delete_databases/rcsb/pdb/data/structures/divided/mmCIF/n4/
[DIR]  ftp://ftp.embl-heidelberg.de/ftp.ebi.ac.uk/pub/delete_databases/rcsb/pdb/data/structures/divided/nmr_restraints/n4/
[DIR]  ftp://ftp.embl-heidelberg.de/ftp.ebi.ac.uk/pub/delete_databases/rcsb/pdb/data/structures/divided/pdb/n4/
[DIR]  ftp://ftp.embl-heidelberg.de/ftp.ebi.ac.uk/pub/delete_databases/rcsb/pdb/data/structures/divided/structure_factors/n4/
[DIR]  ftp://ftp.embl-heidelberg.de/pub/databases/pdb_mirror/current/uncompressed/n4/
[DIR]  ftp://ftp.embl-heidelberg.de/pub/databases/pdb_mirror/current/compressed2/n4/
[DIR]  ftp://ftp.embl-heidelberg.de/pub/databases/pdb_mirror/current/compressed/n4/
[DIR]  ftp://sunsite.univie.ac.at/mirrors/lib.stat.cmu.edu/imsbull/mirror/ims.old/v24/n4/
[DIR]  ftp://sunsite.univie.ac.at/mirrors/lib.stat.cmu.edu/imsbull/mirror/ims.old/v25/n4/
[DIR]  ftp://sunsite.univie.ac.at/mirrors/lib.stat.cmu.edu/imsBulletin/mirror/ims.old/v24/n4/
[DIR]  ftp://sunsite.univie.ac.at/mirrors/lib.stat.cmu.edu/imsBulletin/mirror/ims.old/v25/n4/
[DIR]  ftp://ftp.lug.udel.edu/pub/slackware/slackware-3.4/slakware/n4/