X
- X Libris
- X to the Power of N
- X-S Books
- X-S Books Inc.
- Xamle
- Xanadu Publications Ltd
- Xanadu Publishing Ltd (UK)
- Xanthyros Foundation,Canada
- Xavier Books
- Xcite Books, an imprint of Accent Press Ltd
- XDUP
- Xenos
- Xenos Verlagsgesellschaft
- Xi'an Jiaotong University Press
- Xi'an Press
- Xi'an University of Electronic Science and Technology Publishing House
- XIANGPEIFBH
- XIDATT
- XKSHUO
- XLAHD
- Xlibris
- Xlibris Corporation
- Xlibris Corporation; edition (2010-04-20)
- Xlibris UK
- Xlibris Us
- Xlibris, Corp.
- XML Press
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- XO
- XO - 12 BIS