The intelligence of invertebrate animals

The Mental Life of Monkeys and Apes: A Study of Ideational Behavior

Ways of Nature

Lola

Clever Hans (The Horse of Mr. Von Osten) A contribution to experimental animal and human psychology

Animal Intelligence The International Scientific Series, Vol. XLIV.

Animal Life and Intelligence

Half hours with the lower animals

Animal Behaviour

Intelligence in Plants and Animals Being a New Edition of the Author's Privately Issued "Soul and Immortality."

Animal intelligence: Experimental studies