Correct Citation Format for a Bitcoin Transaction
There is none that I'm aware of, but technically speaking, the blockchain and the transaction hash would suffice to find it. It might be nice to add the block height number as well.

Something like:

Tx 35779d11b2c5aedc1ada50aaa33aafb53ccc07dae71e6d18a35a0ccb872a0efa, Bitcoin Block 342508 


Would work as a citation.