https://www.akc.org/dog-breeds/english-cocker-spaniel/
https://itis.gov/servlet/SingleRpt/SingleRpt
https://www.hillspet.com/dog-care/dog-breeds/english-cocker-spanielhttps://www.britannica.com/animal/dog
https://www.britannica.com/summary/dog
https://www.pbs.org/wnet/nature/dogs-that-changed-the-world-selective-breeding-problems/1281//
https://vittana.org/16-advantages-and-disadvantages-of-selective-breeding