Is it correct to end a letter with the phrase “wa’l-salaam”?
Question

                Brothers end their letters to me with
    "wassalaam", instead of say "assalaamualaikum"can you please tell me if this is correct and the references and their
    authenticity You can also put the question on the web page if you so wish, I need a direct reply since I may not be able to find the answer on
    the web page. Jazzakallaah.
Praise be to Allah.There is nothing wrong with ending a letter with the phrase “wa’l-salaam,”
    and it is not a condition that the phrase should be used in full, because when a written
    abbreviation is used, what the writer means is the complete expression. So when a person
    says “wa’l-salaam,” what he or she means is “wa’l-salaamu
    ‘alaykum.” But if the person sending the letter writes “wa’l-salaamu
    ‘alayka” or “wa’l-salaamu ‘alaykum” at the end,
    this is better. Umar ibn al-Khattaab ended his letter to the qaadi Shurayh with the words
    “wa’l-salaamu ‘alayka” [Sunan al-Nisaa’i, 5304] and
    ‘Umar ibn ‘Abd al-‘Azeez ended his letter to one of his workers in the same
    way [Muwatta’ Malik, Kitaab al-jihaad].
Ibn Katheer reported in al-Bidaayah wa’l-Nihaayah from Ibn
    ‘Asaakir that Ziyaad ibn Abi Sufyaan sent Sa’eed ibn al-‘Aas gifts, money
    and a letter proposing marriage to his daughter. When the gifts, money and letter arrived,
    [Sa’eed] read the letter, shared out the gifts among the people sitting with him,
    then wrote a nice, polite letter back to him in which he said: “In the name of
    Allaah, Most Gracious, Most Merciful. Allaah says: ‘Nay! Verily man does
    transgress all bounds (in disbelief and evil deeds, etc.), because he considers himself
    self-sufficient.’ [al-‘Alaq 96:6-7 – interpretation of the meaning]. Wa’l-salaam.”
However, the person sending the letter should greet the addressee with the
    complete phrase (“Al-salaamu alaykum”) at the beginning of the letter, as
    has been the habit of the Muslims from the time of the Prophet SAWS (peace and blessings
    of Allaah be upon him) until the present. And Allaah knows best.