Translations:Surveys - introduction/139/en

The import process reads the following formats:
 * .LSS files (XML-format created by LimeSurvey 1.90 or later);
 * .LSA files (Survey archive which may include also token, responses and timings - available since LimeSurvey 2.0);
 * .TXT files (Text-format created by Excel - available since LimeSurvey 2.0);
 * .CSV files (Created by early LimeSurvey versions from 1.50 to 1.90).