No, it is not correct. See the sources Writeacher give you.
ok. I am wrong.. sorry.. hehe
Yes, your suggested citation format is correct. To cite the book "Shelly, Cashman, and Vermaat" published in 2006, you would write it as "Shelly et al., 2006" using et al. (an abbreviation for et alia, which means "and others" in Latin) to represent the additional authors besides the first one listed.