BY LINDSAY GOLDWERT / NEW YORK DAILY NEWS
Published: Thursday, May 3, 2012, 8:00 AM
Updated: Thursday, May 3, 2012, 8:00 AM
Tennis superstar Serena Williams said that she has been battling a foe as formidable as her sister, Venus — insomnia.
The grand slam champ is endorsing Sleep Sheets, strips with melatonin that melt in your mouth.