A look at the role that symbolism plays in the novel. In this case, as it is in many other great novels, we see that symbolism is used to enhance the mood and the atmosphere of the novel rather than adding anything of importance to the plot.
Washer, Elise C., "Upside Down World -- the Opposition Between Light and Dark in Bulgakov's Master and Margarita" (2007). Undergraduate Research Symposium (UGRS). 46.