I did source, these are from Pixabay. I make sure I source all the time :) Bottom of the article.
A friend of mine who is a psychotherapist used the famous cat Lil Bub's you tube purr for an infant patient in the hospital. It had some sort of bone condition and the doctors were unsure if it would make it. I cannot remember if the baby was a girl or boy but it did end up puzzling the doctors and healing rapidly.