David Crosby, Stephen Stills and Graham Nash have filled in many of the blanks in their spring and summer tour schedule.

Most of the newly added dates fall in June and July, and extend the trio's tour into late August. Holes still remain in the itinerary, and more dates are expected.

CSN's latest outing comes in the wake of Crosby, Stills, Nash & Young's 2001 and 2002 reunion tours, during which singer-guitarist Neil Young toured with his former bandmates for the first time since 1974.

"After the Storm," CSN's most-recent studio effort, surfaced in 1994. The threesome began work on a follow-up in 1997, and Young signed on during the recording process, which resulted in 1999's "Looking Forward." The set was the first CSNY release since 1988's "American Dream."

CSN formed in 1968 and released their self-titled debut in 1969. Young joined the fold during the group's first tour, and the quartet subsequently released the first CSNY album, titled "Déjà Vu," in 1970. They only made it through that year's summer tour before splitting up on bad terms.

Crosby, Stills and Nash re-teamed in 1977, but didn't record a new album with Young until "American Dream."