"The Red Planet League", inspired not only by "The Red-Headed League" but also by The War of the Worlds and "The Crystal Egg" by H. G. Wells, who makes a cameo appearance.
"The Adventure of the Six Maledictions", inspired by "The Adventure of the Six Napoleons" with mentions of The Jewel of Seven Stars by Bram Stoker and "The Green Eye of the Little Yellow God" by J. Milton Hayes.