Sunan Ibn Majah, Book 7, Hadith 1738 (In-Book) ⓘ
It was narrated that Abu Salamah said: “I heard ‘Aishah say: ‘I used to owe fasts from the month of Ramadan, and I would not make them up for until Sha’ban came.’”
حَدَّثَنَا عَلِيُّ بْنُ الْمُنْذِرِ، حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنْ عَمْرِو بْنِ دِينَارٍ، وَعَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ أَبِي سَلَمَةَ، قَالَ سَمِعْتُ عَائِشَةَ، تَقُولُ إِنْ كَانَ لَيَكُونُ عَلَىَّ الصِّيَامُ مِنْ شَهْرِ رَمَضَانَ فَمَا أَقْضِيهِ حَتَّى يَجِيءَ شَعْبَانُ .
also referenced under: Hadith 1669 (Reference) & Volume 2, Book 7, Hadith 1669 (DarusSalam)