Nurse Pin Up Girl by Gil Elvgren.
Elvgren was a classical American illustrator. He was a master of portraying the all-American ideal feminine, but he wasn't limited to the calendar pin-up industry. He was strongly influenced by the early "pretty girl" illustrators, such as Charles Dana Gibson, Andrew Loomis, and Howard Chandler Christy. Other influences included the Brandywine School founded by Howard Pyle.