Muwatta Malik 685
موطأ مالك#685Sahihحَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ أَبِي سَلَمَةَ بْنِ عَبْدِ الرَّحْمَنِ، أَنَّهُ سَمِعَ عَائِشَةَ، زَوْجَ النَّبِيِّ صلى الله عليه وسلم تَقُولُ إِنْ كَانَ لَيَكُونُ عَلَىَّ الصِّيَامُ مِنْ رَمَضَانَ فَمَا أَسْتَطِيعُ أَصُومُهُ حَتَّى يَأْتِيَ شَعْبَانُ
Yahya related to me from Malik from Yahya ibn Said from Abu Salama ibn Abd ar-Rahman that he heard A'isha, the wife of the Prophet, may Allah bless him and grant him peace, say, "I used to have to make up days from Ramadan and not be able to do them until Shaban came
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 18:1