The door sign for 'Amalgamated Life Insurance' was stuck on with industrial grade mounting tape; a pocket knife was broken trying to peel it off.
A confession magazine can briefly be seen in Dr. Pinero's apartment. The cover contains quotes that are nods to other Robert A. Heinlein novels:
- "I went back in time and had sex with myself" referencing "All You Zombies"
- "How I joined a Martian sex cult" referencing "Stranger in a Strange land"
- "Will the Loonies declare independence" referencing "The Moon is a Harsh Mistress".
When Betty Hartley is introduced she is reading an original copy of the October 1939 edition of "Astounding Science Fiction". The short story "Life-Line" was published in the August issue of that same year.