(a) It is narrated from Abu Uthman al-Nahdi (may Allah have mercy on him) that Sayyiduna Bilal (may Allah be pleased with him) said to the Messenger of Allah (peace and blessings be upon him): "Do not say Amin before me."
It has also been narrated with a weak chain from Asim, from Abu Uthman, from Salman, but that is of no worth; the narration of the group of trustworthy narrators from Asim does not mention Salman.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2299