Translation
(10) The Chapters on Divorce
كتاب الطلاق
(2) Chapter: Divorce according to the Sunnah
(2) باب طَلاَقِ السُّنَّةِ
Sunan Ibn Majah 2020 
It was narrated that Abdullah said:
"Divorce according to the Sunnah means divorcing her when she is pure, ( i.e., not menstruating) and without having had intercourse with her (during that cycle)."
حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ سُفْيَانَ، عَنْ أَبِي إِسْحَاقَ، عَنْ أَبِي الأَحْوَصِ، عَنْ عَبْدِ اللَّهِ، قَالَ طَلاَقُ السُّنَّةِ أَنْ يُطَلِّقَهَا طَاهِرًا مِنْ غَيْرِ جِمَاعٍ ‏.‏
Grade :  Hasan (Darussalam)
Reference : Sunan Ibn Majah 2020
In-book reference : Book 10, Hadith 5
English translation : Vol. 3, Book 10, Hadith 2020