Graded versions of Goldie's theorem

We prove the graded variants of Goldie's theorem of existence, structure and coincidence of right classical and maximal quotient rings of a semiprime (prime) right Goldie's ring (Theorems 10, 11, 13). The main problem, the existence of a homogeneous regular element in each $\operatorname{gr}$-essential right ideal, is solved by posing some additional requirements onto the group grading the ring or onto the homogeneous components of the ring.