Please visit https://www.pnas.org/author-center/after-acceptance#reprints for information about purchasing article reprints. 

Click on the "Login" link on the top right of the home page to get to the login screen. Type your credentials into the username and password fields and click the "Login" button to access your account. You may also log in here.

After logging in, click on My Account. Click on the edit tab (upper right, under My Account). Type your new password into the "password" and "confirm password" fields and save.  After logging in, you may also change your password here.

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Please use the Contact Us form or the form in the Online eBook for all technical-related questions. A representative will respond to your question within 1-2 business days.

In accordance with applicable law, we collect tax in all states of the USA. Sales tax is applied to the total amount of the order and is based on the shipment's destination state and local sales tax rates. Applicable sales tax is charged for electronically delivered products where required by local law. These items are considered to be "shipped" to the address that your order was billed to.

In accordance with applicable law, we collect tax in all states of the USA. Sales tax is applied to the total amount of the order and is based on the shipment's destination state and local sales tax rates. Applicable sales tax is charged for electronically delivered products where required by local law. These items are considered to be "shipped" to the address that your order was billed to.

If your order has been charged tax and you are a tax-exempt organization, we will refund the tax portion of your purchase. To apply for a refund of the tax portion of your order, please follow the procedure below. 

1.  Place your order.

2.  Forward a copy of the received invoice along with a copy of your tax-exempt certificate to:

          Email: estorecancel.sbi@sheridan.com - Attn: Tax Exempt
          Fax: 734.385.1689 - Attn: Tax Exempt

3.  Once your tax information is received, a refund will be issued for the taxes if the order meets the requirements for tax exemption.

We are unable to provide refunds or exchanges, as all products are made-to-order. Please double-check all order details before completing a purchase. If you need assistance with your purchase or there is some other issue with your printed materials, please use the Contact Us form.

You may purchase print issues, journal covers, and journal cover posters from volume 115 (year 2018) to present. Earlier volumes are out of print, and no longer available for purchase.