When I ‘Create Copy as …’ and change the citation style, sometimes the ‘Sources’ disappear. They remain in the document (and in the bibliography) but if you wish to add another reference you find the that the sources option is blank.

When I ‘Create Copy as …’ and change the citation style, sometimes the ‘Sources’ disappear. They remain in the document (and in the bibliography) but if you wish to add another reference you find the that the sources option is blank.