# Transaction Input - previous hash size?

I am reading the bitcoin developer reference and having a look on the transaction input structure. If you have a look here https://bitcoin.org/en/developer-reference#raw-transaction-format it says that the previous output has 36 bytes. I am confused, because I read also the 'Mastering Bitcoin Book' and this wiki page (https://en.bitcoin.it/wiki/Transaction) and they state that the size is 32 bytes.

Is this a mistake in the reference or is it something new which did not propagate to the other sites? Would be nice if someone could clear that up for me :)

outpoint = txid(32 bytes) + output index (4 bytes)