@articleFlögel_Kleine Büning_Lettmann_1993, title=On the restricted equivalence for subclasses of propositional logic, DOI=10.1051/ita/1993270403271, journal=RAIRO - Theoretical Informatics and Applications, author=Flögel, A. and Kleine Büning, H. and Lettmann, Theodor, year=1993, pages=327–340 

@bookDahn_Lettmann_Schönfeld_1991, place=´Heidelberg, series=IWBS Report, title=ILFA Interface Concept, volume=193, publisher=Wissenschaftliche Zentrum der IBM Deutschland , author=Dahn, Bernd I. and Lettmann, Theodor and Schönfeld, Wolfgang, year=1991, collection=IWBS Report 

@articleKleine Büning_Lettmann_Mayr_1989, title=Projections of vector addition system reachability sets are semilinear, DOI=10.1016/0304-3975(89)90055-8, journal=Theoretical Computer Science, author=Kleine Büning, Hans and Lettmann, Theodor and Mayr, Ernst W., year=1989, pages=343–350 

@inproceedingsKleine Büning_Lettmann_1988, place=Berlin, Heidelberg, title=Perspektiven für die Logikprogrammierung, booktitle=Workshop Wissensrepräsentation in Expertensystemen, author=Kleine Büning, Hans and Lettmann, Theodor, editor=Rahmstorf, G.Editor, year=1988, pages=56–78 

@inbookBüning_Lettmann_1987, place=Berlin, Heidelberg, title=Representation independent query and update operations on propositional definite Horn formulas, DOI=10.1007/3-540-18170-9_167, booktitle=Computation Theory and Logic, author=Büning, Hans Kleine and Lettmann, Theodor, editor=Börger, EgonEditor, year=1987, pages=208–223 

@inbookKleine Büning_Lettmann_1986, place=Berlin, Heidelberg, title=Classes of first order formulas under various satisfiability definitions, DOI=10.1007/3-540-16780-3_119, booktitle=8th International Conference on Automated Deduction, author=Kleine Büning, H. and Lettmann, Theodor, year=1986