At one function Switek views an art display of a man and a woman at a table and asks, "You folks from Iowa?" Zito then responds, "I think they're from Ohio." Michael Talbott is a native of Waverly, Iowa, while John Diehl is from Cincinnati, Ohio.
The band playing in the club is Suicidal Tendencies, and the song "Institutionalized".
This episode was called "Free Verse" when it originally aired, but the name was changed to "Zero Solution" for some syndicated broadcasts; however, unlike every other episode that had it's title changed (where the new title became the official one), the episode's name has reverted to "Free Verse" for the show's VHS and DVD releases, and online. Also, unlike most other episodes that received name changes (to link two parts of a single story together), the reasons behind this alteration are unknown.
Sandoval discusses Percy Shelley and William Butler Yeats while at the safe house. He refers to the line "poets are unacknowledged legislators" from "A Defence of Poetry" when discussing the political controversies his work has created in his homeland. When his former student describes himself as a "centrist", Sandoval criticizes this position by quoting Yeats' poem "The Second Coming", which includes the famous line: "the centre cannot hold".