The Globe dedicates some Sunday edition space to looking at the constituents Sam Yoon and Michael Flaherty are courting in order to survive looming preliminary election.

"With fewer than 10 weeks until the field-narrowing Sept. 22 preliminary election, the challengers for mayor in the most competitive race in a generation are counting on a slew of new voters to propel them to the final race. The campaigns of Yoon and Michael F. Flaherty Jr. are pouring resources into finding newcomers to Boston and previously disinterested voters, rather than trying to peel off supporters from Mayor Thomas M. Menino."