The symbol format is given as N() LIJ, where is the particle's approximate mass, L is the orbital angular momentum of the Nucleon-meson pair, produced when it decays, and I and J are the particle's isospin and total angular momentum respectively. Since nucleons are defined as having isospin, the first number will always be 1, and the second number will always be odd. When discussing nucleon resonances, sometimes the N is omitted and the order is reversed, in the form LIJ (); for example, a proton can be denoted as "N(939) S11" or "S11 (939)".