Learn the Art of Combat - Halberd Fighting Fundamentals
Halberd fighting basics from Joachim Meyers book about the knightly art of swordsmanship - 1570 A.D. The description of the chasing hews can be found on page 32recto (XXXII) to 33recto (XXXIII) in the last chapter of the original book found here:
https://daten.digitale-sammlungen.de/0002/bsb00024580/images/index.html?fip=193.174.98.30&id=00024580&seite=1
PS: Obviously NOT exclusive for formation fighting. Meyers manuscript shows mostly techniques for a duel! But you can use many of the concepts also for formation battles like thrusting or striking in a tighter way.