Translation:Mishnah/Seder Nezikin/Tractate Avodah Zarah/Chapter 1/4

English Translation
 It is permitted (to do business) outside of a city that has idol worship inside it. If there is idol worship outside the city, it is permitted (to do business) inside. What about he who should travel to this place --- in the time that the road converges to this place alone, it is forbidden (to do business); but if one can walk on this road from another location, it is permitted (to do business). A city which has in it idol worship and has both decorated and undecorated shop fronts -- this was the case in Beit Shean --- the Sages say: the decorated shops are forbidden (as places in which business can be done) and those shops without decorations are permitted. 

Explanation
עבודה זרה פרק א משנה ד