How did Robert Browning acknowledge John Donne’s influence on dramatic monologues?

Robert Browning explicitly credited John Donne with providing the germ for his own dramatic monologues.1

Browning recognized that Donne’s poetry departed from the conventions of his time by replacing mellifluous lines with a speaking voice that conformed to the needs of specific dramatic situations. This directness, combined with Donne’s ability to render complex states of mind and his use of witty, argumentative language, served as an important impetus for Browning’s own development of the dramatic monologue form.21