all the Arabic works
all the Arabic works had refered to the body of water as persian Gulf , including the world famous Arabic encyclopedia `Al-Monjad' which is the most reliable source in this respect.
There are undeniable legal evidences and documents in confirmation of the genuineness of the term “persian Gulf”. From 1507 to 1560 in all the agreements that Portuguese, Spanish, British, Dutch, French and Germans concluded with all North of the persian Gulf governments or in any other political event everywhere there is a mention of the name persian Gulf
Even in agreements with the participation of the nations north of the persian Gulf there is a mention of "Al-Khalij al-farsi" in the Arabic texts and "persian Gulf" in English texts, such as the document for the independence of Kuwait which was signed between the emir of Kuwait and representatives of the British government in the persian Gulf.