Israel Izak Rubin was found by searching first for Israel Rubin. When the dates found on searches Israel Rubin did not match up wit appropriate birthdates for children, we continued to search for names that "sound like" Israel Rubin. We came across "Izrael" Rubin (with no confirmed middle name found) who was born in an unknown month and day in 1928. There were no other search results that matched up as well, and we concluded that Izrael (with a "z") Rubin was indeed the Israel Izak Rubin that was found in the student names list.
The names submitted for the children under siblings of Israel's are of people who lived at the same address as him who are within a 10 year age range of the year he was born. Whether or not they are just siblings or cousins is hard to say, but they all lived at the same address during the same time, leading us to believe that they are related. The mother, Liba, is estimated to be a young mother (she would have had to be 26 at Israel's birth) as she also lived at the same address as the other two presumed siblings and Israel at the same time.