@book{Schengber2004, author = {Schengber, Ralf}, title = {Handynutzungsverhalten in Deutschland - Eine Studie}, address = {M{\"u}nster}, year = {2004}, language = {mul} } @book{Schengber2005, author = {Schengber, Ralf}, title = {Mobile Marketing - Wir sind noch ganz am Anfang}, year = {2005}, language = {mul} } @article{Schengber2005, author = {Schengber, Ralf}, title = {Killerapplikationen Mobile Marketing}, series = {Marketingjournal}, journal = {Marketingjournal}, year = {2005}, language = {mul} }