Dear readers
The list I presented hear for the Saba'ian rulers , is derived & processed from their inscriptions. Begining of their kingdom is unknown, but may be c. 900 B.C.
Yusif Asar The last of the kings of Saba' is known as "Zinavas" in the local folklor of Arabia & in the Islamic literature.
You can use the unabridged book of Dr. Javad Ali about the history of Arab nations before Islam. this book is translated to persian & I have benefited from it. The main work is in arabic itself.