United Nations Yearbook Series – Online Version
https://www.un.org/en/yearbook
The Yearbook of the United Nations — published by the Department of Global Communications — stands as the authoritative reference work on the activities and concerns of the Organization. Based on official UN documents, the Yearbook provides comprehensive coverage of political and security matters, human rights issues, economic and social questions, legal issues, and institutional, administrative and budgetary matters. Each of the sixty-seven volumes of the Yearbook, dating back to the 1946–47 edition, includes the texts of all major General Assembly, Security Council and Economic and Social Council resolutions and decisions, and places them in a narrative context of UN consideration, deliberation and action.

Security Council Membership Dashboard
https://www.un.org/securitycouncil/content/repertoire/research-tools/scmd
The Security Council Membership Dashboard is elaborated by the Security Council Affairs Division as an interactive information resource. It provides an overview of the composition of the Security Council since 1946, allowing users to visualize the data by year and by elected members. It is updated on an annual basis following the election by the General Assembly in accordance with Article 23 of the Charter of the United Nations.