In 2016, author Rick Riordan published the first book in the Trials of Apollo series, publishing four other books in the series in 2017, 2018, 2019 and 2020.
ɪn tˈuː θˈaʊzənd sˈɪkstiːn, ˈɔːθɚ ɹˈɪk ɹɪˈoːɹdən pˈʌblɪʃt ðə fˈɜːst bˈʊk ɪnðə tɹˈaɪəlz ʌv ɐpˈɑːloʊ sˈɪɹiz, pˈʌblɪʃɪŋ fˈoːɹ ˈʌðɚ bˈʊks ɪnðə sˈɪɹiz ɪn tˈuː θˈaʊzənd sˈɛvəntˌiːn, tˈuː θˈaʊzənd ˈeɪtiːn, tˈuː θˈaʊzənd nˈaɪntiːn ænd tˈuː θˈaʊzənd twˈɛnti.