1.   -- Shelled sunflower seeds and individually wrapped string cheese are handy sources of protein.

2.   However, it already is a handy source of an array of useful information.

3.   The supermarket stock is a handy source in the winter, but true fans of mesclun know that homegrown and fresh is best.

4.   With the growth of the Web, many people have come to view the Internet as a handy source of information.