 Cockburn 's claim is that some of the quotes should not have been cited to their original sources but rather to a secondary source , where he believes I stumbled upon them . Even if he were correct that I found all these quotations in Peters 's book , the preferred method of citation is to the original source , as The Chicago Manual of Style emphasizes : " With all reuse of others ' materials , it is important to identify the original as the source . This ... helps avoid any accusation of plagiarism ... To cite a source from a secondary source ( ' quoted in ... ' ) is generally to be discouraged .... " 
