One reference that also comes to mind is this box from Deary 2001. If we assume "verbal intelligence" to correspond to the "verbal comprehension" group factor in the diagram, and "mathematical reasoning" to correspond to its "perceptual organization" factor (since perceptual organization's associated subtests of picture completion, block design, matrix reasoning, and picture arrangement sound the most similar to Raven's matrices; though "arithmetic" is in the working memory factor) then if I'm thinking about this correct, those two group factors would share 65% (100 * 0.86^2 * 0.94^2) of their variance.