Nokia has sued Apple alleging that Apple's iPhone infringes Nokia patents for GSM, UMTS and wireless LAN (WLAN) standards. They claim to have invested more than EUR 40 billion in R&D during the last two decades. According to Nokia, much of this intellectual property, including the patents in suit, has been declared essential to industry standards. They claim to have license agreements including these patents with approximately 40 companies, including virtually all the leading mobile device vendors.