@article {1990|1638,
	title = {Conformational energy derivatives for polypeptides with flexible proline rings},
	journal = {Comput. \& Chem.},
	volume = {14},
	year = {1990},
	pages = {169{\textendash}175},
	author = {Ruben A. Abagyan and Alexey K Mazur}
}
