TY - JOUR AU - Aleksandar Obradović AU - Slaviša Šalinić AU - Aleksandar Tomović TI - Free vibrations of planar serial frame structures in the case of axially functionally graded materials JO - Theoretical and applied mechanics PY - 2020 SP - 221 EP - 239 VL - 47 IS - 2 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/TAM_2020_47_2_a6/ ID - TAM_2020_47_2_a6 ER -