- FamilySearch Family Tre
- FamilySearch Family Tree (http://www.familysearch.org) - "FamilySearch," database, \i FamilySearch\i0 - The Church of Jesus Christ of Latter-day Saints - accessed 13 Jun 2016), entry for Bertrada, person ID 941K-7T8.
- FamilySearch Family Tree (http://www.familysearch.org) - "FamilySearch," database, \i FamilySearch\i0 - The Church of Jesus Christ of Latter-day Saints - accessed 13 Jun 2016), entry for Countess Of Laon Bertrada, person ID 9SNZ-2JY.
- FamilySearch Family Tree (http://www.familysearch.org) - "FamilySearch," database, \i FamilySearch\i0 - The Church of Jesus Christ of Latter-day Saints - accessed 13 Jun 2016), entry for Bertrada, person ID 941L-LNT.
- FamilySearch Family Tree (http://www.familysearch.org) - "FamilySearch," database, \i FamilySearch\i0 - The Church of Jesus Christ of Latter-day Saints - accessed 13 Jun 2016), entry for Countess Of Laon Bertrada, person ID 9SNZ-LQK.
» Les sources » Arbre généalogique M. Tolsma » Généalogie Online">
- FamilySearch Family Tre
- FamilySearch Family Tree (http://www.familysearch.org) - "FamilySearch," database, \i FamilySearch\i0 - The Church of Jesus Christ of Latter-day Saints - accessed 13 Jun 2016), entry for Bertrada, person ID 941K-7T8.
- FamilySearch Family Tree (http://www.familysearch.org) - "FamilySearch," database, \i FamilySearch\i0 - The Church of Jesus Christ of Latter-day Saints - accessed 13 Jun 2016), entry for Countess Of Laon Bertrada, person ID 9SNZ-2JY.
- FamilySearch Family Tree (http://www.familysearch.org) - "FamilySearch," database, \i FamilySearch\i0 - The Church of Jesus Christ of Latter-day Saints - accessed 13 Jun 2016), entry for Bertrada, person ID 941L-LNT.
- FamilySearch Family Tree (http://www.familysearch.org) - "FamilySearch," database, \i FamilySearch\i0 - The Church of Jesus Christ of Latter-day Saints - accessed 13 Jun 2016), entry for Countess Of Laon Bertrada, person ID 9SNZ-LQK.
» Les sources » Arbre généalogique M. Tolsma » Généalogie Online">