1.https://www.psychologytoday.com/blog/canine-corner/200907/canine-intelligence-breed-does-matter
2.http://www.businessinsider.com/smartest-dog-breeds-2017-1
3.https://www.sciencealert.com/smartest-dog-breeds-according-to-a-canine-psychologist 4.https://www.sciencedirect.com/science/article/pii/S0376635710002925
5.https://link.springer.com/article/10.1007/s10071-012-0494-x.
6.http://dogtime.com/dog-breeds/poodle
7.http://www.akc.org/dog-breeds/german-shepherd-dog/
8.http://dogtime.com/dog-breeds/german-shepherd-dog
9.http://www.akc.org/dog-breeds/golden-retriever/
10.http://www.vetstreet.com/dogs/doberman-pinscher
11.https://www.petmd.com/dog/breeds/c_dg_shetland_sheepdog