One of these was "On the Randian Argument" by libertarian philosopher Robert Nozick, who criticized her meta-ethical arguments.
wˈʌn ʌv ðˈiːz wʌz "ɔnðə ɹˈændiən ˈɑːɹɡjuːmənt" baɪ lˌɪbɚtˈɛɹiən fɪlˈɑːsəfɚ ɹˈɑːbɚt nˈɑːzɪk, hˌuː kɹˈɪɾɪsˌaɪzd hɜː mˈɛɾəˈɛθɪkəl ˈɑːɹɡjuːmənts.