The Puerto Rico salsa/R&B quartet Son by Four once again top the Billboard Latin 50 albums chart with their self-titled disc, which sold one more copy than it did last week, according to sales tracking firm SoundScan.

They hold off the #2 Alma Caribeña — Caribbean Soul by Gloria Estefan for the second straight week.

Estefan may have found a, well, novel way to get even, though. The producers of the upcoming Mexican TV program "Por un Beso," which will begin airing Nov. 20 on Televisa, announced this week that Estefan had agreed to interpret their theme song, a first for the singer. Conveniently, "Por un Beso" (RealAudio excerpt) is the title of the opening track on Alma Caribeña.

Estefan follows the lead of Christian/Latin crossover star Jaci Velásquez's "Llegar a Ti" (RealAudio excerpt) and Son by Four themselves, whose as-heard-on-TV "A Puro Dolor" is at #1 on this week's Hot Latin Tracks chart.

Marc Anthony is at #2 on the tracks survey with "Muy Dentro de Mi (You Sang to Me)" (RealAudio excerpt) and again at #5 on the albums chart with Desde un Principio — From the Beginning. In addition, his English-language "I Need to Know" is included on the #1 pop album in the land, the various-artists collection Now That's What I Call Music! Vol. 4.

The career retrospective Desde un Principio does not include a version of "Hotel California." Last weekend, Anthony surprised and delighted his fans by singing the 1976 Eagles hit at a concert in Puerto Rico, his ancestral home. "This is a song that brings back much of my childhood," he told the crowd. "I have never sung it in public; let's see how it turns out."

Debuting at #8 this week is Obra Maestra (Masterpiece) by Tito Puente and Eddie Palmieri. Recorded shortly before timbales king Puente died at 77 on June 1, Obra Maestra gave jazz great Palmieri "the honor to share the work with my maestro and mentor Tito Puente," he said in a recent interview with the Associated Press. "This album is designed geographically and includes rhythms of multiple countries, but always over the base of salsa."

Rounding out the Latin 50 top 10 are: Julio Iglesias, Noche de Cuatro Lunes, at #3; Omara Portuondo, Buena Vista Social Club Presents Omara Portuondo, at #4; Luis Fonsi, whose Eterno moves to #6 from #10; Alejandro Fernández, Entre Tus Brazos, at #7; Joan Sebastian, Secreto de Amor, at #9; and Thalía, Arrasando, at #10.