Picard mentions the starships Akagi and Hornet. These were the names of two aircraft carriers that fought against each other at the World War II naval battle of Midway.
It is revealed that Data has served in Starfleet for 26 years at this point.
One of the blockade ships is the Sutherland, which is the name of Horatio Hornblower's ship. Gene Roddenberry gave Patrick Stewart several books to read to be used to base his portrayal of Picard on, which included the Horatio Hornblower books by C.S. Forester.
Denise Crosby first suggested the character of Romulan Commander Sela for her to play, having walked away from the character of Lt. Tasha Yar earlier on Star Trek: The Next Generation (1987).