Source;Period;"Number of products"
"Suhara (2000)";1961–1997;100
"Ponomarenko (2002)";1961–1990;117
"Alekseev (1994) and Alekseev et al. (1996)";1976–1994;222
"Smirnov (2013a)";1981–1992;108
"Baranov and Bessonov (1999)+";1990–2006;126
"Baranov and Bessonov (1999)+";1995–2010;236