A computer system and method concurrently present multiple development threads represented by a collection of chronologically-arranged information. An abstraction stack is used to access a body of knowledge stratified into a plurality of levels of abstraction and including a plurality of information...http://www.google.com/patents/US6308187?utm_source=gb-gplus-sharePatent US6308187 - Computer system and method for abstracting and accessing a chronologically-arranged collection of information
