olemus
ISO/IEC/IEEE, ISO/IEC 14764:2006:
kõik tarkvarasüsteemi kuluefektiivseks toetuseks vajalikud enne või pärast tarnimist sooritatavad tegevused
= the totality of activities required to provide cost-effective support to a software system. Activities are performed during the pre-delivery stage as well as the post-delivery stage

ISO/IEC/IEEE, ISO/IEC 19770:
muude õiguste lisamine (näiteks lisafunktsioonide, uuenduse, toe saamiseks) eelnevalt antud tarkvaraõigustele
= entitlement of additional rights (such as additional functionality, upgrade or support) for a previously granted software entitlement

ülevaateid
https://en.wikipedia.org/wiki/Software_maintenance

http://swebokwiki.org/Chapter_5:_Software_Maintenance

https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nbsspecialpublication500-106.pdf

http://www.professionalqa.com/software-maintenance-models