The Talking Machine Forum — For All Antique Phonographs & Recordings

I have in my collection a curious recording of duo from Tonga, the archipelago in South Pacific:

Palu Tupou & Veiongo Fakaua - Pongi Pongi (Song of the Morning) / Kaloni Kakala (song of the evening) - JO 410 - Matrix OEF 271/2

Does anyone have more information about this series featured in this disc, with the prefix -- JO -- ?

Thank you
Emerson