The new Osprey Bouvines 1214 referenced this paper (https://www.academia.edu/35141532/_Les_mercenaire_appel%C3%A9s_Braban%C3%A7ons_aux_ordres_de_Renaud_de_Dammartin_et_leur_tactique_d%C3%A9fensive_%C3%A0_la_bataille_de_Bouvines_1214_in_Revue_du_Nord_99_2017_pp_7_24) (in French) about Renaud de Dammartin's "Brabançon" mercenaries at that battle. I found it on academia.edu; nothing earth-shattering but a decent summary.
Thanks for that. Stretched my French a bit, but it seemed a solid summary. I think he could have found a wider range of examples if he'd looked. The trick of using infantry to form a refuge for knights was used in the wide-ranging tournaments of the 12th century, for example.