Hologram stickers will show the difference between the regular and the fake taxi cabs. By end-January, the special signs will be sticked on all cars in Sofia, sources from the Branch Chamber of Taxi Drivers and Carriers said yesterday. By March 31, the taxi cabs all over the country will have stickers. The measure is taken because of the growing number of irregular yellow cabs that shock customers with blown-up prices for their services. According to the data provided by the branch, at present the irregular taxi cabs account for 30 percent of those on the market.