For an examination of trousers on women, there are many great books and articles on them. For you guys, on googlebooks why not have a look at the Epilogue on female trousers
in Gayle Fischer's Pantaloons & Power: A Nineteenth-century Dress Reform in the United States
. Also have a look at more wider books on fashion - Fashion, Culture and Identity, Fashion and Modernity
(edited by the head of my school), and others on the net.