Everything I've read on it was in books, and my notes from back then are buried in storage somewhere. Wikipedia seems to only have dead links and citations to books published after I studied such material, so I don't know how relevant their citations are. But the topic did come up in various sources as it was discussed in several contexts in what were general courses on ethics or morality. I know it is also a popular topic in some feminist philosophy works, because they like to use animals sometimes as counter-examples to test and contrast moral arguments related to humans, but I didn't study that in very much detail.
Everything I've read on it was in books, and my notes from back then are buried in storage somewhere. Wikipedia seems to only have dead links and citations to books published after I studied such material, so I don't know how relevant their citations are. But the topic did come up in various sources as it was discussed in several contexts in what were general courses on ethics or morality. I know it is also a popular topic in some feminist philosophy works, because they like to use animals sometimes as counter-examples to test and contrast moral arguments related to humans, but I didn't study that in very much detail.