The following publications are possibly variants of this publication:
- Ordering Constraints over Feature Trees Expressed in Second-Order Monadic LogicMartin Müller, Joachim Niehren. RTA 1998: 196-210 [doi]
- Ordering Constraints over Feature TreesMartin Müller, Joachim Niehren, Andreas Podelski. constraints, 5(1/2):7-41, 2000.
- Ordering Constraints over Feature TreesMartin Müller, Joachim Niehren, Andreas Podelski. cp 1997: 297-311
- The first-order theory of ordering constraints over feature treesMartin Müller, Joachim Niehren, Ralf Treinen. dmtcs, 4(2):193-234, 2001. [doi]