(a) It is narrated from Sayyiduna Salamah bin al-Akwa' (may Allah be pleased with him) that he said: I saw the Messenger of Allah (peace and blessings be upon him); he performed ablution and wiped his head once, and he prayed and gave only one salam.
(b) And it is reported from a large group of the Companions that they used to give only one salam.
(c) This is permissible, that is, confining oneself to one is also allowed. And success is from Allah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2989