Remember to distinguish national RC societies from the ICRC where needed. You can refer to examples from between the world wars – e.g. the Italian invasion of Ethiopia and the Spanish Civil War – as they affected Red Cross thinking on neutrality.
The International Review of the Red Cross will discuss the issue.
Also, try a Google Scholar search of ‘Red Cross + neutrality’, or particular conflicts. You will find many sources!
It is important to critically analyze the neutrality of the Red Cross and draw comparisons. You can read literature related to this author, it will help a lot.
Is Neutral Humanitarianism Dead? Red Cross Neutrality: Walking the Tightrope of Neutral Humanitarianism
Rieffer-Flanagan
The International Committee of the Red Cross : a neutral humanitarian actor Rieffer-Flanagan
I will upload relevant courseware and literature later