Fix | broken links at references.md (#180)

Fix broken links at references.md | merging without approvers since it's a very small fix.

docs/user-guide/ref-architecture-aws/references.md

@@ -1,15 +1,15 @@
 # References
 The following are official AWS documentations, blog posts and whitepapers we have considered while building our Reference Solutions Architecture:
 
-- :orange_book: [**CloudTrail for AWS Organizations:**](https://docs.aws.amazon.com/awscloudtrail/latest/userguide/creating-trail-organization.html)
-- :orange_book: [**Reserved Instances - Multi Account:**](https://aws.amazon.com/about-aws/whats-new/2019/07/amazon-ec2-on-demand-capacity-reservations-shared-across-multiple-aws-accounts/)
-- :orange_book: [**AWS Multiple Account Security Strategy:**](https://d0.awsstatic.com/aws-answers/)AWS_Multi_Account_Security_Strategy.pdf
-- :orange_book: [**AWS Multiple Account Billing Strategy:**](https://aws.amazon.com/answers/account-management/)aws-multi-account-billing-strategy/
-- :orange_book: [**AWS Secure Account Setup:**](https://aws.amazon.com/answers/security/aws-secure-account-setup/)
-- :orange_book: [**Authentication and Access Control for AWS Organizations:**](https://docs.aws.amazon.com/organizations/latest/userguide/orgs_permissions.html)
-- :orange_book: [**AWS Regions:**](https://www.concurrencylabs.com/blog/choose-your-aws-region-wisely/)
-- :orange_book: [**VPC Peering:**](https://docs.aws.amazon.com/vpc/latest/peering/what-is-vpc-peering.html)
-- :orange_book: [**Route53 DNS VPC Associations:**](https://aws.amazon.com/premiumsupport/knowledge-center/private-hosted-zone-different-account/)
-- :orange_book: [**AWS Well Architected Framework:**](https://aws.amazon.com/blogs/apn/the-5-pillars-of-the-aws-well-architected-framework/)
-- :orange_book: [**AWS Tagging strategies:**](https://aws.amazon.com/answers/account-management/aws-tagging-strategies/)
+- :orange_book: [**CloudTrail for AWS Organizations**](https://docs.aws.amazon.com/awscloudtrail/latest/userguide/creating-trail-organization.html)
+- :orange_book: [**Reserved Instances - Multi Account**](https://aws.amazon.com/about-aws/whats-new/2019/07/amazon-ec2-on-demand-capacity-reservations-shared-across-multiple-aws-accounts/)
+- :orange_book: [**AWS Multiple Account Security Strategy**](https://d1.awsstatic.com/aws-answers/AWS_Multi_Account_Security_Strategy.pdf)
+- :orange_book: [**AWS Multiple Account Billing Strategy**](https://aws.amazon.com/answers/account-management/)
+- :orange_book: [**AWS Secure Account Setup**](https://aws.amazon.com/answers/security/aws-secure-account-setup/)
+- :orange_book: [**Authentication and Access Control for AWS Organizations**](https://docs.aws.amazon.com/organizations/latest/userguide/orgs_permissions.html)
+- :orange_book: [**AWS Regions**](https://www.concurrencylabs.com/blog/choose-your-aws-region-wisely/)
+- :orange_book: [**VPC Peering**](https://docs.aws.amazon.com/vpc/latest/peering/what-is-vpc-peering.html)
+- :orange_book: [**Route53 DNS VPC Associations**](https://aws.amazon.com/premiumsupport/knowledge-center/private-hosted-zone-different-account/)
+- :orange_book: [**AWS Well Architected Framework**](https://aws.amazon.com/blogs/apn/the-5-pillars-of-the-aws-well-architected-framework/)
+- :orange_book: [**AWS Tagging strategies**](https://aws.amazon.com/answers/account-management/aws-tagging-strategies/)
 - :orange_book: [**Inviting an AWS Account to Join Your Organization**](https://docs.aws.amazon.com/organizations/latest/userguide/orgs_manage_accounts_invites.html)