McLaren Mallite information.

Although I will be sending an e-mail directly to both McLaren applied and McLaren F1 teams directly; I am not particularly hopeful they will respond.

Where else could I find information about mallite? Which was a material they used in the 1960's made of balsa wood and Duralumin (aluminum alloy). Even the wikipedia article is sparse in citations and primary sources. I will also post this in r/McLarenFormula1

Thanks for any help. Even if it just reading.