The unified Expression Language is fairly well documented in the Sun JEE reference documents. A lot of J(2)EE systems use an open-source EL interpreter: the jakarta commons EL project (http://commons.apache.org/el/), which is based on the Jakarta BeanUtils. The BeanUtils are used to resolve property references, so their documentation can be especially helpful.
Some people, when well-known sources tell them that fire will burn them, don't put their hands in the fire.
Some people, being skeptical, will put their hands in the fire, get burned, and learn not to put their hands in the fire.
And some people, believing that they know better than well-known sources, will claim it's a lie, put their hands in the fire, and continue to scream it's a lie even as their hands burn down to charred stumps.