1. https://export.ebay.com/en/start-sell/selling-basics/seller-fees/fees-optional-listing-upgrades/. https://export.ebay.com/en/start-sell/selling-basics/seller-fees/fees-optional-listing-upgrades/.
2. Ctcr implementation. https://github.com/shayg1/CategoryTrees. Ctcr implementation. https://github.com/shayg1/CategoryTrees.
3. Crowdflower search relevance. https://data.world/crowdflower/ecommerce-search-relevance , 2015 . Crowdflower search relevance. https://data.world/crowdflower/ecommerce-search-relevance, 2015.
4. Home depot product search relevance. https://www.kaggle.com/c/home-depot-product-search-relevance/data , 2016 . Home depot product search relevance. https://www.kaggle.com/c/home-depot-product-search-relevance/data, 2016.
5. Innerwear data from victoria's secret and others. https://www.kaggle.com/PromptCloudHQ/innerwear-data-from-victorias-secret-and-others , 2017 . Innerwear data from victoria's secret and others. https://www.kaggle.com/PromptCloudHQ/innerwear-data-from-victorias-secret-and-others, 2017.