Resources for a Page's Contents entry are defined in Resources dictionary of that Page or inherited from one of the ancestor nodes of that Page in the page node tree.
Sunday, February 8, 2009
For XObjects, patterns, Type 3 Fonts and annotations that have content streams, the Resources dictionary will be included in the Content stream's dictionary. Unlike early versions of PDF, Resources cannot be inherited from the page tree for these objects (PDF 32000-1 mentions this obsolete functionality too).
ProcSets are obsolete and are excluded from PDF/D Resource dictionaries.