Scientific References

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3078130/

https://www.researchgate.net/publication/11589760_Causes_of_urine_marking_in_cats_and_effects_of_environmental_management_on_frequency_of_marking

http://content.time.com/time/magazine/article/0,9171,2029480,00.html

https://vet.osu.edu/assets/pdf/hospital/behavior/felineInappropriateElimination.pdf

http://www.catvets.com/public/PDFs/PositionStatements/EarlySpay&Neuter.pdf

http://www.thecatbehaviorclinic.com/cat-urinating-outside-litter-box-problem.html

http://pets.webmd.com/features/pet-pheromone-products-for-behavior-problems

http://www.vet.ohio-state.edu/assets/pdf/education/courses/vm720/topic/indoorcatmanual.pdf

http://www.vet.cornell.edu/fhc/Health_Information/brochure_housesoiling.cfm

http://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=3452