ɪn nˈaɪntiːnhˈʌndɹɪd sˈɛvənti ˈeɪt, pˌiːsˌiːˈɛs wʌz dɪskˈʌst baɪ spˈæɹoʊ ænd bˈɜːd hˌuː ɹᵻpˈoːɹɾᵻd fˈoːɹɾi fˈaɪv wɪð ɪt, ænd ðˌɐɾɪt wʌz pɹˈɑːbəbli mˈoːɹ fɹˈiːkwənt ðɐn dʒˈɛnɚɹəli ɐsˈuːmd.
In 1978, PCS was discussed by Sparrow and Bird who reported 45 with it, and that it was probably more frequent than generally assumed.