If you do not have a Google account, but do have a local account, you can still log in:
by Samuelson, Paul A; Nordhaus, William D; Chaudhuri, Sudip and Sen, Anindya.
by NCERT.
by Dwivedi, D. N.
by Mankiw, N. Gregory.
by Gujarati, Damodar N. ; Porter, Dawn N. and Gunasekar, S.