Anyone got the air ticket from ShangHai PVG to San Fransico SFO...

Anyone got the air ticket from ShangHai PVG to San Fransico SFO(round-trip) during June 15 to July 15? I tried to book the tickets for my parents through the US travel agent, but they said it is hard to get the return one.. Could anyone recommend one in China or US? What's the price? (The agent told me maybe it is easy to book in China)..

Very Very thanks