Possible Clues:

• Brokers' numbers
• Bartlett's collection
• Repeats verbatim
• Repeats precisely
• Cites
• See 36-Across
• Estimates — they include 1, 4 across, 10, 21 and 23 for 18
• In other words, that's what they'll cost
• Uses one's words
• Repeats as from book or speech