Analysis of information sources in references of the Wikipedia article "Chaser (chó)" in Vietnamese language version.
Psychologist John Pilley of Wofford College in Spartanburg, S.C., wanted to test if there was a limit to the amount of words a border collie could learn, so he taught Chaser the names of 1,022 toys, one by one, for three years. New Scientist reports that he got her to fetch the toy and then he repeated the name to reinforce her understanding.
