ɪn nˈaɪntiːnhˈʌndɹɪd fˈoːɹɾi wˈʌn, hiː pɹɪzˈɛntᵻd hɪz θˈiːsɪs "lˌɑːs ˈɑːtʃoʊ ɹiːdʒˈaɪəniz nˈætʃɚɹəlz dˈɛl pˈɛɹuː" æt ðə ɹˌoʊmən θɹˈiː dʒˈɛnɚɹəl ɐsˈɛmbli ʌvðə pˈænɐmˈɛɹɪkən ˈɪnstɪtˌuːt ʌv dʒɪˈɑːɡɹəfi ænd hˈɪstɚɹi.
In 1941, he presented his thesis "Las Ocho Regiones Naturales del Perú" at the III General Assembly of the Pan-American Institute of Geography and History.