1.https://www.avma.org/resources-tools/pet-owners/petcare/senior-pets
2.http://www.pethealthnetwork.com/dog-health/dog-checkups-preventive-care/what-expect-your-senior-dog%E2%80%99s-checkup
3.http://www.vetstreet.com/dogs/caring-for-senior-dogs-what-you-need-to-know
4.http://www.akc.org/content/dog-care/articles/caring-for-older-dog/
5.https://www.petmd.com/dog/grooming/evr_dg_oral_hygiene_and_your_dogs_health
6.http://rng.org.au/wp-content/uploads/2012/07/2010-The-canine-cognitive-dysfunction-rating-scale-CCDR.pdf
7.https://vcahospitals.com/know-your-pet/behavior-counseling-senior-pet-behavior-problems
8.http://vth.vetmed.wsu.edu/specialties/behavioral/ccd-dog-dementia
9.http://leesvilleanimalhospital.com/canine-cognitive-dysfunction-and-your-senior-dog/