The title is a play on "The Adventure of the Greek Interpreter", the short story that introduced Sherlock's brother Mycroft. Incidentally, Sherlock (2010) also changed the title from "Greek" to "geek"; however, it was mentioned in passing rather than the title of the episode.
In the introduction, Sherlock tells Watson he's solved a cold case, the 1926 death of Fitzroy McPherson. He identifies the Lion's Mane jellyfish as the culprit. The victim and jellyfish are directly from "The Adventure of the Lion's Mane," one of the original Sherlock Holmes short stories by Sir Arthur Conan Doyle, published in 1926.
This episode shows several scenes of rain, snow and clear weather over the 72 hours of the supposed duration of the case. The day and night scenes also keep to the timeline acutely. This is not often seen in TV shows.
This episode features a character named Wiggins. Wiggins was the leader of Holmes' Baker Street Irregulars in the original Holmes novels "A Study in Scarlet" and "The Sign of the Four."