[1] Message Transfer Agent (unter X.400)

[2] Multiterminal Adapter (->"IEEE Standard Dictionary")

[3] Maintenance Task Analysis (->"NASA Acronym List")

[4] Mass Thermal Analysis (->"NASA Acronym List")

[5] Major Test Article (->"NASA Acronym List")

[6] Mount Allison university, New Brunswick (Canada, http://www.mta.ca/)