In many cases some recording details remain uncertain. Examples:
1) probably Specled Red on piano;
2) John Smith or Peter James on drums;
3) recorded possibly in (near) 1957;
4) recorded in March 13 or December 21, 1959.
Now in all similar cases we can not reflect correctly this information.
For the case (1) we have three possibilities:
a) do not mention neither Speckled Red nor piano;
b) mention "unknown on piano";
c) mention "Speckled Red performs on piano" as established fact.
Each of these variants is a poor choice.
For the case (2) we can:
a) mention "John Smith performs on drums" and "Peter James performs on drums";
b) mention only "John Smith performs on drums";
c) mention only "Peter James performs on drums";
d) mention "unknown on drums";
e) do not mention neither drums nor drummer.
Each of these variants is a poor choice.
And so on.