Lower Bounds on Consensus

This short note is described by its abstract:

We derive lower bounds on the number of messages and the number of message delays required by a nonblocking fault-tolerant consensus algorithm, and we show that variants of the Paxos algorithm achieve those bounds.
I sent it to Idit Keidar who told me that the bounds I derived were already known, so I forgot about it. About a year later, she mentioned that she had cited the note in:

Idit Keidar and Sergio Rajsbaum. On the Cost of Fault-Tolerant Consensus When There Are No Faults – A Tutorial. MIT Technical Report MIT-LCS-TR-821, May 24 2001. Preliminary version in SIGACT News 32(2), Distributed Computing column, pages 45-63, June 2001 (published in May 15th).
I then asked why they had cited my note if the results were already known. She replied,

There are a few results in the literature that are similar, but not identical, because they consider slightly different models or problems. This is a source of confusion for many people. Sergio and I wrote this tutorial in order to pull the different known results together. Hopefully, it can help clarify things up.