Macdonald Carey's character is named "Burl Stanley Mason," a tongue-in-cheek reference to Earle Stanley Gardner and his famous character, Perry Mason.
One of the victims was found carrying Palladin's business card "Have Gun Will Travel Wire Palladin, San Francisco."
Mad Magazine #93 from December, 1964 has a parody of a children's television program very similar to the one in this episode. Host and all.
Burke's mysterious visitor introduces herself as Mary, which Burke calls "a grand old name". This is a reference to one of George M. Cohan's most famous songs, which describes the name Mary as "a grand old name:"