Rollings, Andrew; Ernest Adams (2006). Fundamentals of Game Design. Prentice Hall. Archivado desde el original el 31 de diciembre de 2017. Consultado el 5 de agosto de 2014.
rakrent.com
«RTS Basics: R & D». and the StarCraft manual. Although multi-epoch games like the Age of Empires and Empire Earth series have a larger number of research options and a significant proportion of civilian research options, the research options all depend on having the right buildings. See the relevant games' manuals.
web.archive.org
Rollings, Andrew; Ernest Adams (2006). Fundamentals of Game Design. Prentice Hall. Archivado desde el original el 31 de diciembre de 2017. Consultado el 5 de agosto de 2014.
