Some notes by Santasiere:
18. 0-0? "After 18.Nc3! White's game is probably won. If then 18...Nxf3+ 19.Bxf3 Qe5 20. Nd5! Qa1+ 21.Bd1! and not 21.Qd1 because of 21...Bc3+."
After 26.Nb5: "I thought my chances more than good in this ending, but White's c-pawn must be held or Black's b-pawn captured."
27. Rb1? "27.f4! relieves the mating threat and threatens Rd7, Nd6, etc."
"The game took fifteen hours -- and much of it in time pressure for both players! Imagine playing rapid transit by radio!"