https://linkinghub.elsevier.com/retrieve/pii/0376507577900083
http://linkinghub.elsevier.com/retrieve/pii/S0020737375800058
https://linkinghub.elsevier.com/retrieve/pii/B9780122669507500062
http://www.tandfonline.com/doi/abs/10.1080/00140136908931076