Start with high-confidence british & irish poetry books, then narrow by subgenre or adjacent topics.
English Literature in the Sixteenth Century (excluding Drama)
C. S. Lewis
Old English Literature
Fred Robinson
Approaches to Teaching Coleridge's Poetry and Prose
Richard E. Matlak
Paradise Regained
John Milton
A Lover's Complaint
William Shakespeare
Aurora Leigh
Elizabeth Barrett Browning
Love Three
Aaron Kunin