^Garner and Rosen, Moral Philosophy, chapter 13 ("Noncognitivist Theories") and Brandt, Ethical Theory, chapter 9 ("Noncognitivism") regard the ethical theories of Ayer, Stevenson and Hare as noncognitivist ones.
^Ogden and Richards, Meaning, 125: "'Good' is alleged to stand for a unique, unanalyzable concept … [which] is the subject matter of ethics. This peculiar ethical use of 'good' is, we suggest, a purely emotive use. … Thus, when we so use it in the sentence, 'This is good,' we merely refer to this, and the addition of "is good" makes no difference whatever to our reference … it serves only as an emotive sign expressing our attitude to this, and perhaps evoking similar attitudes in other persons, or inciting them to actions of one kind or another." This quote appears in an extended form just before the preface of Stevenson's Ethics and Language.
^Philosophy of Meaning, Knowledge and Value in the Twentieth Century: Routledge History of Philosophy. Routledge. 2012. ISBN9781134935727.
^Pepper, Ethics, 277: "[Emotivism] was stated in its simplest and most striking form by A. J. Ayer."
^Brandt, Ethical Theory, 239, calls Stevenson's Ethics and Language "the most important statement of the emotive theory", and Pepper, Ethics, 288, says it "was the first really systematic development of the value judgment theory and will probably go down in the history of ethics as the most representative for this school."
^Brandt, Ethical Theory, 221: "A recent book [The Language of Morals] by R. M. Hare has proposed a view, otherwise very similar to the emotive theory, with modifications …"
^Wilks, Emotion, 79: "… while Hare was, no doubt, a critic of the [emotive theory], he was, in the eyes of his own critics, a kind of emotivist himself. His theory, as a consequence, has sometimes been depicted as a reaction against emotivism and at other times as an extension of it."