Gotts, N. M. (2000). "Emergent phenomena in large sparse random arrays of Conway's 'Game of Life'". International Journal of Systems Science. 31 (7): 873–894. doi:10.1080/002077200406598. S2CID34979810.
entropymine.com
For this reason, Jason Summers' life status page describes a rake as a "versatile puffer", and collects data on the existence of rakes for various speeds and periods of puffers.
Gotts, N. M. (2000). "Emergent phenomena in large sparse random arrays of Conway's 'Game of Life'". International Journal of Systems Science. 31 (7): 873–894. doi:10.1080/002077200406598. S2CID34979810.