Reference. Rectangles, curves, and {Klein} bottles [schwartz-2022-rectangles]

@article{schwartz-2022-rectangles,
	author = {Schwartz, Richard Evan},
	title = {Rectangles, curves, and {Klein} bottles},
	journal = {Bulletin of the American Mathematical Society},
	volume = {59},
	year = {2022},
	pages = {1--17},
	doi = {10.1090/bull/1755},
	mrnumber = {4340824},
	msc2020 = {51M04},
	note = {Published electronically: September 13, 2021}
}