Paul Simon and Art Garfunkel continue to confirm new shows for their upcoming summer tour, which so far is scheduled to visit more than a dozen U.S. markets.

The duo, who last year mounted a reunion tour after a 10-year separation, have scheduled about a month of dates in June and July. Tickets for some shows are on sale now, and others will hit the box office in the coming days, according to promoters.

The official Simon & Garfunkel [ tickets ] website plans to offer a limited number of pre-sale tickets; details are posted at the site.

Last year's Simon & Garfunkel tour emerged in the wake of their performance at the 2003 Grammy Awards, where they received the Lifetime Achievement Award. The event marked their first performance together in a decade.

Prior to last year's outing, Simon & Garfunkel had not toured together since the early eighties; the pair did, however, give a number of New York City concerts in 1993.

According to concert-industry magazine Pollstar, last year's tour grossed $64.4 million over 39 shows, enough to place it at No. 6 on Pollstar's year-end list.

As a duo, Simon & Garfunkel have sold more than 40 million albums in the U.S., according to a tour publicist. They were inducted into the Rock and Roll Hall of Fame in 1990.

Last fall, Columbia/Legacy released "The Essential Simon and Garfunkel," a two-disc career retrospective.