Well, therein lies a problem. You *can't tell* from the text itself - it doesn't explicate everything. It isn't an encyclopedia. The authors and translators generally expected individuals to either have the context for the references, or to have a priest or religious leader to give you that context. When those books were collected int the Bible, nobody expected you to be able to pick up the book (presuming you could read it) and know everything you needed to know.
The Bible (both Old and New Testament)... are kind of like comic books. There's a core story, but it often makes references to things more fully described in other works (for the Christians, the extras are often collectively called Apocrypha - the books that didn't make the cut when the current books of the Bible were chosen - in the 1500s and 1600s, depending on the denomination) that aren't part of the main collection. Reading the Bible is kind of like reading the Marvel Comics "Secret Wars" miniseries, but not reading all the crossover issues in the other titles. Or, like current Star Wars, with the Expanded Universe stories that aren't considered canon.
That's where we get the word canon, from, by the way. The books the church says are the accepted ones are the church canon.