Large and complex computer based systems are the result of an evolution process which may take many years. Heterogeneity is an important characteristic of such systems: During the evolution process, different technologies were used for development; different third-party products were integrated into the system; information about the system components is often incomplete, scattered over a company and comes in various formats. To support the development of large systems, this information has to be collected and integrated into architectural models. Hence, architecture elicitation of a large computer based system has to cope with the heterogeneity of technology and information sources. Some information can be extracted and prepared by tools, but the majority is usually inside documents and the heads of the developers. Therefore, in addition to tool support, this task requires a lot of ion which can only be done by humans. This paper presents concepts and abstractions for integrative mode...