A concept drawing of the development and angle of the icebreaker bow.
Source: KA, HR, 21. The drawing dates from the 1940s during the design of icebreaker Voima. It was digitized, digitally rearranged and enhanced by Aaro Sahari.
The International Journal of Maritime History has a scholarly explanation of the evolution of icebreaker design. There is also an accompanying podcast from CIMSEC, if you prefer that format, but you would miss a lot.
Chuck Hill's CG Blog 
I really appreciate Dr Sahari’s and Dr Matala’s work around the history of icebreakers and winter navigation because they are not afraid of challenging and even debunking some of the quite nationalistic narrative originating from the “icebreaking-industrial complex”.
Here’s another article that, while focusing on other issues, also touches the technological aspects of Baltic Sea icebreakers:
https://www.tandfonline.com/doi/full/10.1080/07341512.2017.1343909
There is also an article on the Finnish-Soviet co-operation on nuclear-powered icebreakers, but unfortunately I could not find a freely accessible version.