Possible Clues:

• Abbr. meaning "in the same place," in footnotes
• Ref. citation
• Abbr. meaning 'in the same place,' in footnotes
• Bibliog. equivalent of 'ditto'
• How I get a lot from the same place
• Common abbr. in footnotes
• How one makes an offer for what's in the same place, in short
• Shortened word meaning in the same place
• Footnote 'ditto'
• Prev. cited in a footnote