%0 Journal Article %T AUTOMORPHISM GROUP OF GROUPS OF ORDER pqr %J Algebraic Structures and Their Applications %I Yazd University %Z 2382-9761 %A Ghorbani, M. %A Nowroozi Larki, F. %D 2014 %\ 02/01/2014 %V 1 %N 1 %P 49-56 %! AUTOMORPHISM GROUP OF GROUPS OF ORDER pqr %K Affine group %K Frobenius group %K Automorphism group %R %X H\"{o}lder in 1893 characterized all groups of order $pqr$ where  $p>q>r$ are prime numbers. In this paper,  by using new presentations of these groups, we compute their full automorphism group. %U https://as.yazd.ac.ir/article_413_d618acbaf2f7c98f8667ef4ce3c65ab7.pdf