ˈæftɚ ɹᵻsˈiːvɪŋ stɹˈɔŋ ɹᵻspˈɑːns fɹʌm ˈɛɹpleɪ ˌɔn ɐmˈɛɹɪkən "ˌʌndɚɡɹˈaʊnd" ˌɛfˈɛm ɹˈeɪdɪˌoʊ, lˈɪbɚɾi ˈɪʃuːd ðə sˈɔŋ æz ɐ sˈɪŋɡəl ˌɔn ˈeɪpɹəl twˈɛnti fˈoːɹ, nˈaɪntiːnhˈʌndɹɪd sˈɪksti ˈeɪt.
After receiving strong response from airplay on American "underground" FM radio, Liberty issued the song as a single on April 24, 1968.