Abu Mu'awiyah from Yahya bin Sa'id, and Ibrahim bin Muhammad from Yahya bin Sa'id, from Nafi', from Sayyiduna Ibn Umar (may Allah be pleased with them both): that he saw no harm in a man selling something of his to a known term while he did not have its source (the actual goods) with him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 11093