A bibliogram is a graphical representation of the frequency of certain target words, usually noun phrases, in a given text.
The noun phrases in the ranking may be authors, journals, subject headings, or other indexing terms.
A bibliogram is verbal construct made when noun phrases from extended stretches of text are ranked high to low by their frequency of co-occurrence with one or more user-supplied seed terms.
The "core" consists of relatively few top-ranked terms that account for a disproportionately large share of co-occurrences overall.
The descriptors are ranked by how many of her articles they were used to index: This author is a researcher in education, and it will be seen that the terms profile her intellectual interests over the years.