Actually I think when Joel says "that old mantra" he's not trying to avoid citing Brooks, but instead assuming his audience are already familiar with that work.
I don't think The Second-System Effect, which is the chapter of Brooks most relevant to this discussion, comes close to listing all the problems Joel hits on, and its examples are inevitably dated. The dusty copy on my shelf proudly states that it is the "20th anniversary edition".
For example, in the chapter's section describing why OS/360 is "a pile" Brooks offers the example of 26 bytes he sees as being "wasted" on handling the correct behaviour of the new year in leap years, insisting that this situation should instead be handled by the operator. So, every four years Brooks proposes that the inevitable skeleton staff left on duty while others party should undertake a tricky manual change to the system precisely at midnight, in order to reduce the size of the system by 26 bytes. A modern student encountering this paragraph would be right to snort at the lack of foresight in such an assertion and perhaps to raise an eyebrow at the apparent implication that Brooks was in favour of the sort of shortcuts that led to the "Millennium Bug".