Mumbai, Jan 9: The Tata group's global e-learning firm, Tata Interactive Systems (TIS) has acquired two European software companies for an undisclosed amount. TIS acquired Tertia Edusoft Gmbh in Germany and Tertia Edusoft AG in Switzerland from the Tertia Group of companies. TIS CEO Sanjaya Sharma told FE, "The acquisitions will add about 20-25% to our revenues. The German company is a market leader in the simulations space and along with the Swiss entity, it will open up the non-English speaking markets of Europe and give us access to the leading businesses in central Europe.