Access control

Considering ISO 27001, I suggest these articles from Advisera:

• How to handle access control according to ISO 27001 https://advisera.com/27001academy/blog/2015/07/27/how-to-handle-access-control-according-to-iso-27001/
• How two-factor authentication enables compliance with ISO 27001 access controls https://advisera.com/27001academy/blog/2017/01/16/how-two-factor-authentication-enables-compliance-with-iso-27001-access-controls/
• The most common physical and network controls when implementing ISO 27001 in a data center https://advisera.com/27001academy/blog/2019/02/26/the-most-common-physical-and-network-controls-when-implementing-iso-27001-in-a-data-center/
• How to protect against external and environmental threats according to ISO 27001 A.11.1.4 https://advisera.com/27001academy/blog/2016/01/25/how-to-protect-against-external-and-environmental-threats-according-to-iso-27001-a-11-1-4/

Considering other sources, I suggest:

• NIST Special Publication 800-53 (Rev. 4) - Security and Privacy Controls for Federal Information Systems and Organizations https://nvd.nist.gov/800-53/Rev4/family/Physical%20and%20Environmental%20Protection 

These materials can also help you:

• ISO 27001 Annex A Controls in Plain English https://advisera.com/books/iso-27001-annex-controls-plain-english/
• ISO 27001 Foundations Course https://advisera.com/training/iso-27001-foundations-course/