Notes on Entries. This is a personal selection. Notes on Annotations. I sometimes try also to explain idiosyncratic terminology, in order to make it easier to read the original item. It is normally finite unless otherwise indicated.
Sigma is a signed graph.
Phi is a gain graph. Omega is a biased graph. I cannot name all the people who have contributed advice and criticism, but many of the annotations have benefited from suggestions by the authors or others and a number of items have been brought to my notice by helpful correspondents. I am very grateful to you all. Thanks also to the people who maintain the invaluable MR and Zbl.