Zehoo, Edmund (26 January 2010). Zehoo, Edmund (ed.). Pro ODP .NET for Oracle Database 11g. Apress. pp. 351–371. doi:10.1007/978-1-4302-2821-9_13 – via Springer Link.
Hussain, Shahid; Keung, Jacky; Khan, Arif Ali (2017). "The Effect of Gang-of-Four Design Patterns Usage on Design Quality Attributes". 2017 IEEE International Conference on Software Quality, Reliability and Security (QRS). pp. 263–273. doi:10.1109/QRS.2017.37. ISBN978-1-5386-0592-9. S2CID21343926.
Hunt, John (26 January 2013). Hunt, John (ed.). Scala Design Patterns: Patterns for Practical Reuse and Design. Springer International Publishing. pp. 135–136. doi:10.1007/978-3-319-02192-8_16 – via Springer Link.
Hussain, Shahid; Keung, Jacky; Khan, Arif Ali (2017). "The Effect of Gang-of-Four Design Patterns Usage on Design Quality Attributes". 2017 IEEE International Conference on Software Quality, Reliability and Security (QRS). pp. 263–273. doi:10.1109/QRS.2017.37. ISBN978-1-5386-0592-9. S2CID21343926.