The "graph classes: a survey" mentioned Trotter and other authors have presented a list of forbidden subgraph of comparability graph. But the google book( where I read graph classes: a survey) do not have the page which contains the reference of specific literature. To my knowledge, one forbidden graph is "a k-cycle ( k is an odd intege $\ge$ 5) and no triangle chord".
Thank you for your help in advance. :-)