With Greece’s coffers deep in the red, its government is on the hunt for new sources of income. Now Athens has embarked on an ambitious program to find tax evaders. Greek tax investigators are poring through aerial photos on the Internet, searching for luxurious villas with large swimming pools.Many of these villas were built with untaxed income. And the tax authorities are increasingly hearing that wealthy Greeks are moving their money abroad. Turkey is a popular destination because Turkish banks have a reputation for stability. But even ordinary Greek wage-earners are affected by the new government’s new tax-collecting zeal, and will now be asked to obtain receipts even for small purchases.