Heinrich Bullinger was very interested in persuading the Danes that the Swiss Reformation was worth considering (rather than the Lutheran) and he wrote De gratia Dei justificante nos propter Christum per solam fidem absque operibus bonis, fide interim exuberante in opera bona, libri IV. ad sereniss. Daniæ regem Christianum to prove it.
It is such a well written book that none less than Philip Melanchthon thought very highly of it!
Nevertheless, the Danish Reformation, led by Hans Tausen, was and remained essentially Lutheran (which explains why Danes are not as Reformed as they should be…)