@article{SH2007a
 author    = {Schmidt, Renate A. and Hustadt, Ullrich},
 title     = {The Axiomatic Translation Principle for Modal Logic},
 journal   = {ACM Transactions on Computational Logic},
 volume    = {8},
 number    = {4},
 year      = {2007},
 pages     = {19/1--55},
}