You can find general basic information on reciprocity on Wikipedia. Some books on reciprocity are: Reciprocity, by Lawrence Baker, A cooperative species: Human reciprocity by Lawrence Baker, Trust and Reciprocity: Interdisciplinary Lessons for experimental research, by Elinor Ostrom.

Does virginia have reciprocity for tickets with delaware?

in the fraction 9/10 the positive reciprocity is 9

As far as I can tell, none.

Of the states that do offer reciprocity, all of them require that the state in which the attorney sits offer reciprocity to them, as well. SD does not allow reciprocity with any state, so no state will allow reciprocity with SD.

Reciprocity is the idea of mutual give-and-take, like if you give me your notes from the class I missed, I'll bake you cookies as reciprocity.