Microservice scalability can be achieved in various ways depending on the type of scalability needed. Here are some types of scalability and their examples with references:

1. Horizontal scalability: This type of scalability involves adding more instances of the same service to handle increasing loads. For example, if a service is running on a single server and the load increases, more servers can be added to handle the load.
2. Vertical scalability: This type of scalability involves adding more resources to a service instance to handle increasing loads. For example, if a service is running on a single server and the load increases, more memory or CPU can be added to the server to handle the load.
3. Elastic scalability: This type of scalability involves automatically adding or removing instances of a service based on the demand. For example, if a service is experiencing high traffic, more instances of the service can be added automatically to handle the load, and when the traffic reduces, the instances can be removed automatically.
4. Stateful scalability: This type of scalability involves scaling services that maintain state. For example, if a service is maintaining a database, the service can be scaled by sharding the database across multiple instances.
5. Combinatorial scalability: This type of scalability involves combining multiple microservices to handle increased loads. For example, if a user request requires the coordination of multiple microservices, more instances of each microservice can be added to handle the increased load.

These types of scalability can be used in combination to achieve the required level of scalability for a microservice-based application.