1. Macura, L., Voznak, M. (2012). Embedded multiplatform SIP server solution. In 35th International Conference on Telecommunication and Signal Processing, TSP2012 (pp. 263–266).
2. AsteriskNOW, a complete Linux distribution with Asterisk, the DAHDI driver framework, and, optionally, the FreePBX administrative GUI. http://www.asterisk.org/downloads/asterisknow .
3. LANDIVAR, Edgar. (2011). Unified Communications with Elastix, Vol. ASIN B0056IXJRC.
4. uElastix, embedded variant of Elastix distribution. http://uelastix.org/ .
5. Madsen, L., Meggelen, J., & Bryant, R. (2011). Asterisk: The definitive guide. Sebastopol: O’Reilly Media.