Hadith 516670
Chapter 49: The Description of the Prophet, may Allah Bless Him and Grant Him Peace - كتاب صفة النبى صلى الله عليه وسلم
وَحَدَّثَنِي مَالِكٌ، عَنْ أَبِي جَعْفَرٍ الْقَارِيِّ، أَنَّهُ قَالَ رَأَيْتُ عَبْدَ اللَّهِ بْنَ عُمَرَ يَشْرَبُ قَائِمًا .
Yahya related to me from Malik that Abu Jafar al-Qari said, "I saw Abdullah ibn Umar drink while standing."
Reference Muwatta Malik 516670
USC-MSA web (English) reference : Book 49, Hadith 15