In the bibliographic index, when there are multiple authors there should be a comma separating the names, including the first name listed, even if there are only 2 authors.

For example, there should be a comma after Anne-Birgitte in the first example and a comma after Kathleen in the second example:

Fonsmark, Anne-Birgitte and Dorthe Vangsgaard Nielsen. ""Introduction."" In Impressionism and Its Overlooked Women, edited by Dorthe Vangsgaard Nielsen, pp. 7–13. Charlottenlund: Ordrupgaard, 2024

Adler, Kathleen and Tamar Garb. Berthe Morisot. Ithaca, New York: Cornell University Press, 1987.