@article{10_4064_sm_95_1_93_106,
     author = {Waldemar Hebisch},
     title = {Sharp pointwise estimate for the kernels of the semigroup generated by sums of even powers of vector fields on homogeneous groups},
     journal = {Studia Mathematica},
     pages = {93--106},
     publisher = {mathdoc},
     volume = {95},
     number = {1},
     year = {1989},
     doi = {10.4064/sm-95-1-93-106},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-95-1-93-106/}
}