The Book of Drinks
51/9. Chapter:
Mixing Al-Busr and Dried Dates (At-Tamr)
Sunan an-Nasai
أَخْبَرَنَا أَحْمَدُ بْنُ سُلَيْمَانَ، قَالَ حَدَّثَنَا يَزِيدُ، قَالَ أَنْبَأَنَا حُمَيْدٌ، عَنْ عِكْرِمَةَ، عَنِ ابْنِ عَبَّاسٍ، قَالَ الْبُسْرُ وَحْدَهُ حَرَامٌ وَمَعَ التَّمْرِ حَرَامٌ.
It was narrated that Ibn 'Abbas said: "Al-Busr on their own are unlawful and with dried dates they are unlawful."
Reference : Sunan an-Nasa'i 5558In-book reference : Book 51, Hadith 19English translation : Vol. 6, Book 51, Hadith 5560