Riina Maigre Pavel Grigorenko Peep Küngas Enn Tyugu Stratified Composition of Web Services. 49-58 2008 JCKBSE http://dx.doi.org/10.3233/978-1-58603-900-4-49 conf/jckbse/2008 db/conf/jckbse/jckbse2008.html#MaigreGKT08