The Brady Bunch : An Outrageously Funny, Far-Out Guide To America's Favorite TV Family
by Sylvia Stoddard
St. Martin's Paperbacks December 15, 1996
on Page 98:
"... and Sonny and Cher. Barry Williams remembers the beginnings. "The singing and dancing kind of evolved. Back then, the Cowsills were popular, the Osmonds were pop- ular, the Partridge Family had come out, and we liked to sing and dance ..."