P. S. Krøyer's paintings of his wife Marie
... that among P. S. Krøyer's paintings of his wife Marie is a double portrait in which they painted each other?
... that among <b id="mwCUk"><a href="./P._S._Krøyer's_paintings_of_Marie" id="mwCUo" rel="mw:WikiLink" title="P. S. Krøyer's paintings of Marie">P. S. Krøyer's paintings of his wife Marie</a></b> is a double portrait <i id="mwCUs">(pictured)</i> in which they painted each other?