References
- Mark Gregorek et al. (U.S. patent 5,321,740) Neil Sleevi (U.S. patent 4,811,382)
Karl Seelig et al. (U.S. patents 7,006,608 and 7,227,929)
Read more about this topic: Ringback Tone
References
Karl Seelig et al. (U.S. patents 7,006,608 and 7,227,929)
Read more about this topic: Ringback Tone