```ruby
require 'active_triples'
require 'linked_vocabs'

module DPLA
  require 'dpla/source_resource'
  require 'dpla/collection'
  require 'dpla/place'
  require 'dpla/time_span'
  require 'dpla/aggregation'
  require 'dpla/web_resource'
end
```

Use autoload for Resource classes
user
```ruby
require 'active_triples'
require 'linked_vocabs'

module DPLA
  autoload :SourceResource,     'dpla/source_resource'
  autoload :Collection,         'dpla/collection'
  autoload :Place,              'dpla/place'
  autoload :TimeSpan,           'dpla/time_span'
  autoload :Aggregation,        'dpla/aggregation'
  autoload :WebResource,        'dpla/web_resource'
end
```
assistant