You schedule looks pretty good to me. I have come up with the following where the referees are in square brackets:
(B C) (G F) [D A]
(E H) (D A) [B C]
(C J) (B I) [E H]
(G D) (F A) [I J]
(I E) (H J) [G F]
(G B) (F C) [H A]
(H A) (E D) [G I]
(J F) (G I) [E D]
(H C) (E B) [J F]
(D I) (A J) [B C]
(E F) (G H) [I J]
(A B) (C D) [E F]
(I J) [C]
(C G) (A E) [B D]
(B D) (F H) [A G]
(I A) (J E) [C H]
(B H) (D F) [G J]
(C I) (J G) [A E]
I am not sure what criteria you will used to evaluate how good the schedule is, so let me know what you think.