from Masato:

These ballad books are online at Internet Archive: Text Archive.

English And Scottish Popular Ballads, ed. George Lyman Kittredge (abridged one-volume ed.)

The English and Scottish Popular Ballads (parts 1, 2, 4, 5, 6, 7, 8 and 9), ed. Francis James Child.

The English And Scottish Popular Ballads, Volumes I & V, ed. Francis James Child (Folklore Press reprint editions, 1956)

English and Scottish Ballads, 8 vols., ed. Francis James Child (1860 edition)

Reliques of Ancient English Poetry, 3 vols. (MDCCXCIV and MDCCCXXXIX editions) - Thomas Percy

Bishop Percy's Folio Manuscript : Ballads and Romances, 3 vols. (1867-68) ["Loose and Humorous Songs" is not available]

Popular Ballads and Songs, 2 vols. - Robert Jamieson

Minstrelsy : Ancient and Modern (1827) - William Motherwell

Minstrelsy of the Scottish Border, by Sir Walter Scott, 4 vols., edited by T.F. Henderson (1902)