A part of collecting that I enjoy the most is the research.
Thanks to other collectors and and also the manufacturers of dolls we can keep the history and the facts connected.
Places I like to visit and I will link to as long as they are available online are:
Sindy
Mansell, Colette (1999). The history of Sindy: Britain's top teenage doll 1962–1994
https://www.pedigreetoysandbrands.co.uk/our-brands/sindy/
https://thelittlesindymuseum.com
https://jenjoysalldolleduppage.wordpress.com/2023/05/08/sindy-doll-mie-and-mihk-comparison/
Tammy
Izen, Judith (2005). Ideal Dolls: Identification and Values
Fleur
Susi
https://bonecasusimuseuvirtual.blogspot.com/
https://www.estrela.com.br/bonecas/cl%C3%A1ssicas
Bibi-Bo
https://corporate.e-jumbo.gr/uploads/157038/BABr_inrep_061107_160.pdf
https://www.elgrecoandlyratoys.org/
https://www.persephone-dragonfly.com/bibi-bo-rapunjel/index.php